JP6918996B2 - Thermal spraying material, thermal spray coating and member with thermal spray coating - Google Patents

Description

The present invention relates to a thermal spraying material, a thermal spray coating formed by using the thermal spraying material, and a member with a thermal spray coating.

Techniques for imparting new functionality by coating the surface of a base material with various materials have been conventionally used in various fields. As one of the surface coating techniques, for example, sprayed particles made of a material such as ceramics are sprayed on the surface of a base material in a softened or melted state by combustion or electric energy to form a sprayed coating made of such a material. The thermal spraying method is known.

Further, in the field of manufacturing semiconductor devices and the like, the surface of a semiconductor substrate is generally microfabricated by dry etching using a plasma of a halogen-based gas such as fluorine, chlorine or bromine. Further, after dry etching, the inside of the chamber (vacuum container) from which the semiconductor substrate is taken out is cleaned using oxygen gas plasma. At this time, in the chamber, members exposed to highly reactive oxygen gas plasma or halogen gas plasma may be corroded. Then, when the corroded (erosion) portion falls off from the member in the form of particles, the particles can become foreign substances (hereinafter, the foreign substances are referred to as particles) that adhere to the semiconductor substrate and cause defects in the circuit.

Therefore, conventionally, in semiconductor device manufacturing equipment, in order to reduce the generation of particles, a ceramic sprayed coating having plasma erosion resistance has been provided on a member exposed to plasma such as oxygen gas or halogen gas. ing. For example, Patent Document 1 discloses that yttrium oxyfluoride can have high plasma erosion resistance, and granules (granulated particles) containing yttrium oxyfluoride in at least a part of yttrium oxyfluoride are used as a material for thermal spraying. It is described that it is used as.

International Publication No. 2014/002580 Japanese Patent No. 5911036

However, as described in Patent Document 2, the thermal spraying material containing yttrium oxyfluoride is different from the case where another thermal spraying material is used because fluorine becomes a gas and volatilizes during the formation of the thermal spray coating. In comparison, it became clear that there was a drawback that it was difficult to form a dense thermal spray coating. Further, there is also a problem that it is difficult to control the composition of the compound constituting the thermal spray coating due to the change in the composition of the thermal spraying material during thermal spraying. As the degree of integration of semiconductor devices has improved, more precise control of contamination by particles has been required, and finer particles are also generated in the thermal spray coating of ceramics provided in semiconductor device manufacturing equipment. (Improvement of dust generation resistance) is required.

In view of such a situation, it is an object of the present invention to provide a thermal spraying material capable of forming a dense thermal spray coating having excellent plasma erosion resistance and dust generation resistance. Another object of the present invention is to provide a thermal spray coating and a member with a thermal spray coating formed by using this thermal spraying material.

The present invention provides a thermal spraying material having the following characteristics as a solution to the above problems. That is, the material for spraying disclosed herein contains rare earth elements, oxygen and halogen elements as constituent elements, and is characterized by containing a mixed crystal of a rare earth element oxyhalide and a rare earth element halide.

Rare earth element oxyhalides are known to be superior in plasma erosion resistance to halogen-based plasmas as compared with, for example, rare earth element halides and rare earth element oxides. However, conventional materials for spraying containing a rare earth element oxyhalide have been produced as a mixture with a rare earth element halide and / or a rare earth element oxide, for example, as disclosed in Patent Document 1. Further, in the rare earth element oxyhalide, the halogen element easily volatilizes when exposed to a high temperature spraying environment, and the composition of the sprayed coating formed is significantly different from the composition of the sprayed material used. Typically, the composition of the thermal spray coating could be such that the thermal spray material was oxidatively decomposed into oxides. That is, even if the rare earth element halide remains in the sprayed coating, the proportion of the rare earth element oxide obtained by decomposing the rare earth element oxyhalide could be higher. This rare earth element oxide is a source of fine particles that have not been controlled so far, and it is not preferable that the rare earth element oxide is contained in the sprayed coating. Further, as pointed out in Patent Document 2, the sprayed coating formed tends to contain a relatively large number of pores due to the volatilization of the halogen element.

On the other hand, according to the study by the present inventors, a mixed crystal of a rare earth element oxyhalide and a rare earth element halide is, for example, a rare earth element halogen, although it is a material for spraying containing rare earth elements, oxygen and halogen elements. It was found that it is difficult to be oxidatively decomposed when exposed to the spray environment, not only when compared with the simple substance of the compound, but also when compared with the simple substance of the rare earth element oxyhalide or a mixture thereof. It was also found that the chemical composition of the decomposition product remains very high on the rare earth element oxyhalide side even when the mixed crystal is oxidatively decomposed. In other words, it is difficult to decompose into rare earth element oxides by thermal spraying. The techniques disclosed herein are based on such findings. As a result, the content of rare earth element halides and / or rare earth element oxides is suppressed, and a thermal spraying material capable of forming a thermal spray coating having plasma erosion resistance and dust generation resistance against halogen-based plasma is realized. .. Further, a thermal spraying material capable of forming a thermal spray coating having a reduced porosity while containing a rare earth element oxyhalide is provided.

In a preferred embodiment of the thermal spraying material disclosed herein, it may be in a form substantially free of the rare earth element halide which is the halide of the rare earth element. In addition, it may be in a form that does not substantially contain the rare earth element oxide, which is the oxide of the rare earth element. That is, it is possible to prevent the rare earth element halide and the rare earth element oxide, which are inferior in plasma erosion resistance to the rare earth element oxyhalide, from being contained at the stage of the thermal spraying material.
This makes it possible to more reliably improve the dust generation resistance of the thermal spray coating formed by thermal spraying.
In addition, in this specification, "substantially free of" a predetermined compound may mean, for example, that the compound is not detected in X-ray diffraction analysis.

In a preferred embodiment of the thermal spraying material disclosed herein, it may be in a form substantially free of the rare earth element oxyhalide. This provides a thermal spraying material that is even more resistant to oxidation in a thermal spraying environment.

In a preferred embodiment of the thermal spraying material disclosed herein, the proportion of the rare earth element halide in the mixed crystal is 5 mol% or more and 95 mol% or less. As a result, the oxidative decomposition of mixed crystals in the thermal spraying environment can be stably suppressed.

In a preferred embodiment of the material for spraying disclosed herein, itolium is contained as the rare earth element, fluorine is contained as the halogen element, yttrium oxyfluoride is contained as the rare earth element oxyhalide, and the rare earth element halide is contained. Includes Fluoride Itrim. This provides, for example, a thermal spraying material capable of suitably forming a thermal spray coating having excellent erosion resistance to fluorine plasma and dust generation resistance.

A preferred embodiment of the thermal spraying material disclosed herein is a powder having an average particle size of 5 μm or more and 60 μm or less. As a result, a thermal spraying material having excellent fluidity and high thermal spraying efficiency is provided.

A preferred embodiment of the thermal spraying material disclosed herein is that the cumulative pore volume of the powder having a pore radius of 1 μm or less is 0.1 cm ³ / g or less. By making the thermal spraying material dense in this way, it is possible to suppress the oxidation of the thermal sprayed particles constituting the powder in the thermal spraying environment at a high level. In addition, the denseness of the thermal spray coating formed by using this thermal spraying material can be enhanced.

In another aspect, the present invention provides a thermal spray coating containing a rare earth element oxyhalide containing a rare earth element, oxygen and a halogen element as a main component and having a porosity of 5.5% or less.
The thermal spray coating disclosed here is realized as a dense thermal spray coating having a porosity of 5.5% or less while containing a rare earth element oxyhalide as a main component. That is, although the thermal spraying material is deposited in a sufficiently melted or softened state by thermal spraying, a dense thermal spray coating is formed in a state where oxidation is suppressed. As a result, the thermal spray coating is provided as having reliably improved plasma erosion resistance and dust generation resistance.

A preferred embodiment of the sprayed coating disclosed herein is substantially free of the rare earth element halide, which is the halide of the rare earth element. In addition, the mode may be substantially free of the rare earth element oxide, which is the oxide of the rare earth element. It is preferable that the sprayed coating does not contain a rare earth element halide and / or a rare earth element oxide because the dust generation resistance is surely improved.

In a preferred embodiment of the spray coating disclosed herein, itolium is contained as the rare earth element, fluorine is contained as the halogen element, yttrium oxyfluoride is contained as the rare earth element oxyhalide, and fluorine is contained as the rare earth element halide. Includes fluorinated it rim. With such a configuration, for example, a thermal spray coating having excellent erosion resistance to fluorine plasma and dust generation resistance can be formed.

Further, the member with a thermal spray coating provided by the technique disclosed herein is characterized in that the surface of the base material is provided with the thermal spray coating according to any one of the above. With such a configuration, a coated member having excellent plasma erosion resistance and dust generation resistance is provided.

It is a figure which illustrated the XRD diffraction pattern result of four powders (a)-(d). It is a flowchart which illustrated the manufacturing method of the thermal spraying material which concerns on one Embodiment. It is a figure explaining the manufacturing method of the thermal spray coating which concerns on one Embodiment. (A1) and (B1) are examples of transmission electron microscope (TEM) images of the cross section of the sprayed coating before and after alteration, and (A2) and (B2) are diagrams schematically explaining the alteration of the sprayed coating. (A) is an observation image obtained by spraying the thermal spraying material of Example 5 and observing a cross section of the thermal spray coating with a scanning electron microscope (SEM), and (b) is a partially enlarged view thereof. (A) is an observation image obtained by spraying the thermal spraying material of Example 8 and observing a cross section of the thermal spray coating by SEM, and (b) is a partially enlarged view thereof. It is a figure exemplifying the result of observing the thermal spray coating obtained by thermal spraying of the thermal spraying material of a reference example by SEM.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention can be grasped as design matters of those skilled in the art based on the prior art in the art. The present invention can be carried out based on the contents disclosed in the present specification and common general technical knowledge in the art. In the specification, the notation "XY" indicating the numerical range means "X or more and Y or less" unless otherwise specified.

[Material for thermal spraying]
The thermal spraying material disclosed herein contains a rare earth element (RE), an oxygen (O) and a halogen element (X) as constituent elements. The thermal spraying material is characterized by containing a mixed crystal of a rare earth element oxyhalide (RE-OX) and a rare earth element halide (RE-X). Since the rare earth element oxyhalide and the rare earth element halide form a mixed crystal, the solid solution ratio of each composition is changed even in a high temperature environment by spraying, and a stable state can be maintained. It is considered that oxidative decomposition into compounds (for example, Y ₂ O ₃ and F _{2) can be suppressed.}

Here, the mixed crystal means a substance in which two or more substances having different chemical compositions are uniformly mixed with each other to form a crystallographically substantially uniform solid phase. Mixed crystal is a meaning that also includes concepts such as the terms "solid solution" and "alloy" that are mainly used for metal materials. In the techniques disclosed herein, rare earth element oxyhalide (RE-OX), which is a compound of rare earth element (RE), oxygen (O) and halogen element (X), and rare earth element (RE) and halogen. The rare earth element halide (RE-X), which is a compound of the element (X), forms a mixed crystal. At this time, in the mixed crystal composition, the rare earth element oxyhalide may be in a state in which a relatively large amount of halogen element is contained in the crystal phase based on the presence of the rare earth element halide. For example, the rare earth element oxyhalide can be understood to be in a state where the halogen element is supplied (doped) from the rare earth element halide.

Further, since two or more different compounds form a mixed crystal, for example, even if the element ratio of the elements constituting these compounds changes depending on the spray environment, the mixing ratio of the compound in the mixed crystal It can be absorbed as a change in (hereinafter referred to as "solid solution ratio", etc.). For example, the present inventors have confirmed that rare earth element oxyhalides and rare earth element halides form mixed crystals in almost the entire composition range (total mixing ratio) excluding pure components. That is, the mixed crystal of the rare earth element oxyhalide and the rare earth element halide can be a total solid solution. As a result, the thermal spraying material disclosed herein is in a mixed crystal state without causing a chemical reaction such as decomposition of a compound or a large change in the crystal structure even if the halogen element is volatilized by being exposed to the thermal spraying environment. Can be maintained.

Specifically, for example, yttrium oxyfluoride (Y ₅ O ₄ F ₇ ) and yttrium fluoride (YF ₃ ) are easily oxides alone in a thermal spraying environment based on the following equations (1) and (2). Will be directly decomposed. As a result, rare earth element oxides and halogen gases are produced.
Y ₅ O ₄ F ₇ + 7 / 4O ₂ → 5 / 2Y ₂ O ₃ + 7 / 2F ₂ ↑… (1)
YF ₃ + 1 / 2O ₂ → Y ₂ O ₃ + 3F ₂ ↑… (2)
However, since these compounds are mixed crystals, as shown in the following formula (3), even when the halogen gas is volatilized by being oxidized in a thermal spraying environment, it is oxidized by changing the mixed crystal composition. Decomposition into substances is suppressed.

_{(Y 5 O 4 F 7 -6YF} 3) + 2O 2 → (2Y 5 O 4 F 7 -YF 3) + 4F 2 ↑ ... (3)
(2Y ₅ O ₄ F _7- YF ₃ ) + 2O ₂ → 3Y ₅ O ₄ F ₇ + 4F ₂ ↑ + 4F ₂ ↑… (4)
Y ₅ O ₄ F ₇ + 1 / 2O ₂ → 3YOF + 7 / 2F ₂ ↑… (5)
Further, as shown in the above formula (4), in the mixed crystal, it is possible to suppress the direct decomposition into oxides until the thermal spraying material becomes a pure component. When the mixed crystal has a solid solution limit, it is suppressed from being directly decomposed into an oxide until it has a solid solution limit composition. Further, even when the mixed crystal is oxidatively decomposed, the chemical composition of the decomposition product can be led to the rare earth element oxyhalide side which is one compound (pure component) constituting the mixed crystal. Further, when the rare earth element oxyhalide is a compound having a high proportion of halogen elements, as shown in the above formula (5), it is changed to a rare earth element oxyhalide having a lower proportion of halogen elements and then oxidized. Form an object. As a result, the formation of rare earth element oxides can be further suppressed. As a result, although the material for spraying disclosed herein contains rare earth elements, oxygen and halogen elements, for example, when compared with a simple substance of rare earth element halides, of course, rare earth element oxyhalides Even when compared with simple substances or mixtures thereof, they are less likely to be oxidatively decomposed when exposed to a spray environment. It should be noted that the above-mentioned action and effect are characteristics peculiar to the thermal spraying material, and may be a remarkable effect exerted regardless of the thermal spraying method.
In the above formula, for example, reference to a _{"(Y 5 O 4 F 7 -6YF} 3) " _is, Y ₅ O 4 _{F 7} and YF ₃ in a molar ratio were mixed 1: 6 ratio of mixed It means that it forms crystals.

In the technique disclosed herein, the rare earth element (RE) constituting the mixed crystal is not particularly limited, and can be appropriately selected from the elements of scandium, yttrium and lanthanoid. Specifically, scandium (Sc), yttrium (Y), lantern (La), cerium (Ce), placeodium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), Gadrinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), yttrium (Yb) and lutetium (Lu). From the viewpoint of improving plasma erosion resistance and relatively low price, Y, La, Gd, Tb, Eu, Yb, Dy, Ce and the like are preferable. The rare earth element may contain any one of these elements alone, or may contain two or more of them in combination.

Further, the halogen element (X) is not particularly limited, and may be any element belonging to Group 17 of the Periodic Table of the Elements. Specific examples thereof include halogen elements such as fluorine (F), chlorine (Cl), bromine (Br), iodine (I) and astatine (At). Preferably, it can be F, Cl, Br. These may contain any one kind alone, or may contain two or more kinds in combination.

Here, the composition of the rare earth element oxyhalide (RE-OX) constituting the mixed crystal is not particularly limited. The combination of the rare earth element (RE) and the halogen element (X) constituting the rare earth element oxyhalide and the ratio of the rare earth element (RE), the halogen element (X) and the oxygen (O) are not particularly limited. For example, as the rare earth element oxyhalide, oxyfluoride, oxychloride and oxybromide of various rare earth elements are typical examples. Since this rare earth element oxyhalide forms a mixed crystal with the rare earth element halide described later, it is preferable that the rare earth element oxyhalide has a crystal structure common to such a rare earth element halide. Such a crystal structure may be, for example, cubic crystal, tetragonal crystal, rhombic crystal, hexagonal crystal, orthorhombic crystal (orthorhombic crystal), monoclinic crystal, triclinic crystal or the like. Among them, as the rare earth element oxyhalide, for example, it is known that the corrosion resistance to halogen-based plasma is relatively high. General formula: RE ₁ O _1-n F _{1 + 2n} (n in the general formula is 0 ≦ n). It is preferably an orbital crystal and / or a rhombohedral crystal having a crystal structure of an oxyfluoride of a rare earth element represented by <1.); Preferably, it may be an orthorhombic crystal having a crystal structure when n in the above general formula is 0 <n <1.

The composition of the rare earth element halide (RE-X) constituting the mixed crystal is not particularly limited. The combination of the rare earth element (RE) constituting the rare earth element halide and the halogen element (X) and the ratio thereof are not particularly limited. For example, as the rare earth element halide, various rare earth element fluorides, chlorides and bromides are typical examples. Since this rare earth element halide forms a mixed crystal with the above-mentioned rare earth element oxyhalide, it is preferable to have a crystal structure common to such a rare earth element oxyhalide. Such a crystal structure may be, for example, cubic crystal, tetragonal crystal, rhombic crystal, hexagonal crystal, orthorhombic crystal (orthorhombic crystal), monoclinic crystal, triclinic crystal or the like. Among them, orthorhombic and / or rhombohedral crystals are preferable, and orthorhombic crystals are more preferable. The rare earth element halide having an orthorhombic crystal structure may be, for example, a rare earth element fluoride represented by the _{general formula: REF 3; which is known to have relatively high corrosion resistance to halogen-based plasma.} ..

In order for the rare earth element halide and the rare earth element oxyhalide to form a mixed crystal, it is preferable that the crystal lattices (unit cells) are close in size. Therefore, the rare earth element halide and the rare earth element oxyhalide can contain a rare earth element common to each other. For example, the rare earth element oxyhalide and the rare earth element contained in the rare earth element halide are 50 mol% or more (preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more, respectively. For example, 95 mol% or more, substantially 100 mol%) may be common elements.

The rare earth element oxyhalide and the rare earth element halide may have the same or similar crystal structure even when the rare earth element and the halogen element are different. Therefore, as one preferred form below, the rare earth element contains yttrium (Y), the halogen element contains fluorine (F), the rare earth element halide contains yttrium fluoride (YF ₃ ), and the rare earth element oxyhalide. May include the case where yttrium oxyfluoride (YOF) is contained. Such yttrium oxy fluoride, for example, thermodynamically stable, the ratio of the yttrium, oxygen and halogen element 5: 4: 7 Chemical composition and _Y 5 _O 4 _{F 7,} other YOF, _{Y 6} General formulas such as O ₅ F ₈ , Y ₇ O ₆ F _9, Y ₁₇ O ₁₄ F _{23, etc .: Y 1} O _1-n F _{1 + 2n} (in the general formula, 0 <n <1 is satisfied); It may be a compound or the like. In particular, it may be _{Y 5} O ₄ F ₇ which can form a suitable mixed crystal with yttrium fluoride and has a high ratio of fluorine to oxygen. In the following description, part or all of yttrium (Y) can be replaced with an arbitrary rare earth element, and part or all of fluorine (F) can be replaced with an arbitrary halogen element.

In the mixed crystals disclosed herein, the ratio of the rare earth element oxyhalide to the rare earth element halide (sometimes referred to as the solid solution ratio) is not particularly limited. By mixing (solid-solving) the rare earth element halide with the rare earth element oxyhalide, the ratio of the halogen element to the rare earth element contained in the mixed crystal is increased, and the rare earth element oxyhalide It is preferable because the oxidative decomposition of the element is suppressed. From this point of view, the ratio of the rare earth element halide to the total of the rare earth element oxyhalide and the rare earth element halide constituting the mixed crystal is preferably 5 mol% or more, preferably 20 mol% or more. More preferably, it is particularly preferably 40 mol% or more, and for example, it can be 50 mol% or more. As an example, it may be 60 mol% or more or 70 mol% or more. However, if the proportion of the rare earth element halide in the mixed crystal is excessive, the halogen element tends to volatilize in a high temperature environment at the time of thermal spraying, and there is a possibility that it is difficult to contribute to oxidation suppression. From this point of view, the ratio of the rare earth element halide in the mixed crystal is preferably 95 mol% or less, more preferably 90 mol% or less, and particularly preferably 85 mol% or less.

More directly, the spraying material disclosed herein contains a mixed crystal of a rare earth element oxyhalide and a rare earth element halide as described above, and thus is a spraying material composed of a rare earth element oxyhalide. The proportion of halogen elements is higher than that. In such a material for spraying, the ratio of the halogen element to the total of the rare earth element, oxygen, and halogen element is preferably 45 atomic% or more, more preferably 50 atomic% or more, for example 53 atomic% or more. However, even if the thermal spraying material contains an excessive amount of halogen element, it is not preferable because the halogen element easily volatilizes from the thermal spraying material during thermal spraying. Therefore, in the material for spraying, the ratio of the halogen element to the total of the rare earth element, oxygen, and halogen element is preferably 73 atomic% or less, more preferably 70 atomic% or less, for example, 65 atomic% or less.

The method for confirming that the mixed crystal is contained in the thermal spraying material is not particularly limited, but can be carried out by, for example, the following method.
First, the composition and crystal structure of the thermal spraying material are examined by X-ray Diffraction (XRD) analysis. The XRD diffraction pattern of the mixed crystal can be observed, for example, in a form in which each of the diffraction patterns of the two compounds constituting the mixed crystal is shifted to the low angle side, for example. Therefore, first, the crystal structure of the substance contained in the thermal spraying material is specified by XRD analysis of the thermal spraying material. At this time, if a rare earth element oxyhalide or a rare earth element halide is identified separately from the mixed crystal, it is preferable to specify the composition (valence, element ratio) as well. Then, in the obtained diffraction pattern, when the diffraction patterns of the rare earth element oxyhalide and the rare earth element halide constituting the mixed crystal are both shifted while maintaining their shapes, the diffraction pattern is observed. It can be determined that a mixed crystal of these rare earth element oxyhalides and rare earth element halides is contained.

For example, FIG. 1 shows images of XRD diffraction patterns of the four powders (a) to (d). The vertical lines in FIG. 1 are _{the main peak position of the YF 3} crystal phase (27.881 °), the main peak position of the YOF crystal phase (28.064 °), and the main of the Y ₅ O ₄ F ₇ crystal phase from the left side. peak position (28.114 _°), shows the main peak position of the Y 2 _{O 3} crystal phase (29.157 °) respectively. The peak near 31 ° is a peak attributed to _{YF 3.}
Here, the powder (d) is _{a mixed powder obtained by mixing YF 3} powder and Y ₅ O ₄ F ₇ powder, and the XRD pattern includes a diffraction peak based on the _{YF 3 crystal phase and Y 5} O ₄ F ₇ Diffraction peaks based on the crystal phase are observed respectively. Further, the powder (a) is a calcined powder obtained by calcining _{YF 3} granulated powder, and a diffraction peak based on the YOF crystal phase is slightly observed in the diffraction peak based on the _{YF 3 crystal phase which is the main phase.} The powder (b) is a granulated powder of _{YF 3} powder and Y ₂ O _{3 powder, and diffraction peaks based on the YF 3} crystal phase and the Y ₂ O ₃ crystal phase are observed, respectively. The powder (c) is a mixed crystal powder composed of a mixed crystal of _{YF 3} powder and Y ₅ O ₄ F _{7 powder as raw materials.} However, the XRD pattern of the powder (c) is a diffraction peak attributed to the YF ₃ crystal phase and _Y 2 _{O 3} crystal phase is not observed. It can be seen that the XRD pattern of the powder (c) corresponds to the diffraction pattern of the compound (d), which is a mixed powder of _{the YF 3} powder and the Y ₅ O ₄ F _{7 powder, shifted to the low angle side.} .. For example, in this way, the content of mixed crystals can be confirmed.

The presence of mixed crystals can also be confirmed by X-ray Photoelectron Spectroscopy (XPS). However, it can be difficult to perform XPS analysis on powdered thermal spraying materials. Therefore, with respect to the thermal spraying material, the presence or absence of mixed crystals can be suitably confirmed by the above-mentioned XRD analysis. Although not particularly limited, the presence or absence of mixed crystals can be confirmed by, for example, XPS analysis for the sprayed coating described later. The presence or absence of mixed crystals can also be confirmed by XPS analysis for some thermal spraying materials.
In the confirmation of mixed crystals by XPS analysis, first, the constituent elements of the thermal spraying material and their electronic states are measured by XPS analysis or the like. By irradiating the thermal spraying material with X-rays, electrons in atomic orbitals are excited and emitted as photoelectrons. Since the binding energy of the electrons emitted at this time is the orbital energy peculiar to each element and its oxidation state, the types of elements constituting the injection material and its oxidation by measuring the X-ray photoelectron spectroscopy spectrum are used. You can get information about the condition. For example, the elemental distribution on the surface of the material for spraying (typically a surface depth of several nanometers) can be measured, and the rare earth element (RE), halogen element (X), contained in the material for spraying can be measured. And the atomic ratio of oxygen (O) can be grasped.

Further, for example, the XPS spectrum of the 3d orbital of a rare earth element (yttrium in the following example) has two components, so that it is separated into _{3d 5/2} and 3d _3/2. The 3d _5/2 peak appears on the low energy side, and the 3d _3/2 peak appears on the high energy side. Table 1 shows the metal yttrium (Y), yttrium oxide (Y ₂ O ₃ ), yttrium oxyfluoride (YOF, Y ₅ O ₄ F ₇ ), yttrium halide (YF ₃ , YBr ₃ , YCl 3, _{YCl 3).} An example of measuring the electron binding energy of 3d _5/2 orbitals in YI ₃ ) and their mixed crystals (Y ₂ O ₃ / Y, YOF / Y ₂ O ₃ , YF ₃ / Y ₅ O ₄ F _7). Indicated. As shown in Table 1, for example, it can be seen that _{the 3d 5/2 peak of the mixed crystal appears between the 3d 5/2} peaks of the compound forming the mixed crystal. Specifically, for example, the XPS peak of the 3d _{5/2 orbital of yttrium fluoride (YF 3} ) appears at about 159.5 to 160.5 eV. For reference, _{the XPS peak of the 3d 3/2} orbital of yttrium fluoride appears in the vicinity of 161.2 eV. On the other hand, for example, the XPS peak of the 3d _{5/2 orbital of Y in yttrium oxyfluoride (Y 5} O ₄ F ₇ ) appears between approximately 158.25 and 159 eV. The XPS peak of the 3d orbit in the mixed crystal of yttrium oxyfluoride and yttrium fluoride (YF ₃ / Y ₅ O ₄ F ₇ ) is between the peak in yttrium oxyfluoride and the peak in yttrium fluoride (YF 3 / Y 5 O 4 F 7). It will appear in 159.0 to 159.5 eV). However, at this time, for mixed crystals _{, no peak for 3d 3/2} is observed on the high energy side. In other words, in mixed crystals, the XPS spectrum of the yttrium 3d orbital can be aggregated to _{the 3d 5/2 peak on the low energy side.} The details of this phenomenon are not clear, but it is considered that the 3d _3/2 peak of yttrium disappears or shifts significantly to the _{3d 5/2 side.} Then, it can be confirmed that the mixed crystal contains a mixed crystal of yttrium oxyfluoride and yttrium fluoride by observing one XPS peak in the energy range of at least 157 to 159 eV. As specifically shown in the examples described later, for example, when the thermal spray coating contains mixed crystals, only one XPS spectrum of the 3d orbital of yttrium is observed, and the second peak on the high energy side is not observed. .. From this, it is said that the thermal spray coating in the present specification contains a mixed crystal of yttrium oxyfluoride and yttrium fluoride at a position _{where the XPS spectrum derived from the 3d orbital of yttrium for the material is close to the 3d 5/2 orbital.} It can be understood that it is agreed that only one is observed in the range (for example, approximately 159 to 159.5 eV). Alternatively, it can be understood that it is agreed that the peak _{of 3d 3/2} is not seen on the high energy side.

The ratio (solid solution ratio) of the rare earth element oxyhalide and the rare earth element halide in the mixed crystal can be grasped from, for example, the ratio of the main peaks of the rare earth element oxyhalide and the rare earth element halide in the XRD analysis. can do. More specifically, for example, several types of mixed crystal samples in which the solid solution ratios of the rare earth element oxyhalide and the rare earth element halide are changed are prepared, and XRD analysis is performed on each sample to perform a predetermined peak (for example, each). Create a calibration line showing the relationship between the peak height of the main peak of the phase and the solid solubility rate. Then, by applying the height of the peak derived from the mixed crystal of the material for spraying to which the solid solution rate is to be measured to this calibration curve, the solid solution rate (content) of the rare earth element oxyhalide and the rare earth element halide can be obtained. Can be quantified. The solid solution rate can also be quantified for the XPS spectrum position of the 3d orbital of yttrium in the XPS analysis of mixed crystals by similarly adopting the calibration curve method. The method for confirming the presence of mixed crystals and the calculation of the solid solution ratio thereof are not limited to the above examples, and those skilled in the art can appropriately adopt various appropriate analytical methods.

Further, when analyzing the composition of the thermal spraying material, for example, an energy dispersive X-ray spectroscopy (EDX) method may be adopted. By performing EDX analysis, the constituent elements of the thermal spraying material can be analyzed from the surface to a depth of about several tens of μm to several cm, and the bulk composition can be grasped accurately.

By including this mixed crystal in the thermal spraying material as much as possible, it is possible to suppress the oxidative decomposition of the thermal spraying material during the thermal spraying. That is, during thermal spray coating formed, an oxide of rare earth element poor耐発dust (e.g., yttria (Y 2 _{O 3))} to reduce the rate that contain higher or than the oxygen content of the rare earth element oxyfluoride be able to. In addition, it is possible to suppress the inclusion of air bubbles in the thermal spray coating due to oxidative decomposition of the thermal spray material, and it is possible to form a dense thermal spray coating. Therefore, the ratio of mixed crystals may be contained in the thermal spraying material even in a small amount (for example, 1% by mass or more), but in order to clearly obtain such an effect, for example, the ratio of mixed crystals is 30. It is preferably 5% by mass or more, more preferably 50% by mass or more, further preferably 75% by mass or more, and particularly preferably 80% by mass or more. The proportion of the mixed crystal may be 90% by mass or more, 95% by mass or more, 98% by mass or more, for example, 99% by mass or more. Substantially 100% by mass of the thermal spraying material may be a mixed crystal.
In addition, in this specification, "substantially 100% by mass" is a predetermined compound (for example, mixed crystal), for example, in X-ray diffraction analysis, excluding unavoidable impurities, the compound (for example, mixed crystal). It is possible that compounds other than) are not detected.

Further, the spraying material, a mixed crystal or a rare earth element oxyhalide, compared to the rare earth element fluoride, containing rare earth element oxides poor耐発Dust (typically alone, for example, Y _{2 O 3)} Is preferably suppressed. The rare earth element oxide is preferably 10% by mass or less, preferably 5% by mass or less, and particularly preferably 3% by mass or less of the thermal spraying material. For example, it is more preferable that the thermal spraying material is substantially free of rare earth element oxides.

Similarly, it is preferable that the thermal spraying material contains a rare earth element halide (typically a simple substance, for example, YF ₃ ) that does not form a mixed crystal. The rare earth element halide is preferably 20% by mass or less, preferably 10% by mass or less, particularly preferably 5% by mass or less, and may be, for example, 3% by mass or less. For example, it is more preferable that the thermal spraying material is substantially free of rare earth element halides.

Further, the thermal spraying material is preferably contained in the rare earth oxyhalide that does not constitute a mixed crystal (typically alone, for example, YOF and Y _{5 O} 4 _{F 7)} is suppressed. The rare earth element oxyhalide is preferably 20% by mass or less, preferably 10% by mass or less, particularly preferably 5% by mass or less, and may be, for example, 3% by mass or less. For example, it is more preferable that the thermal spraying material is substantially free of the rare earth element oxyhalide.

The rare earth element oxide contained in the thermal spraying material can be directly contained as a rare earth element oxide in the thermal spray coating by thermal spraying. For example, yttrium oxide contained in a thermal spraying material can exist as yttrium oxide as it is in a thermal spray coating by thermal spraying. This rare earth element oxide (for example, yttrium oxide) has lower plasma resistance than the rare earth element oxyhalide. Therefore, the portion containing the rare earth element oxide tends to form an extremely brittle altered layer, and the altered layer becomes fine particles when exposed to halogen-based plasma and easily desorbs. Then, these fine particles may be deposited on the semiconductor substrate as particles. Therefore, in the thermal spraying material disclosed herein, the inclusion of a rare earth element oxide in which an altered layer serving as a particle source is likely to be formed is excluded. Furthermore, although rare earth element oxyhalides have relatively high plasma erosion resistance, halogens are easily volatilized in a plasma environment, and some of them are oxidatively decomposed to have a higher oxygen content. It tends to be easily decomposed into oxides. Therefore, in the thermal spraying material disclosed herein, the rare earth element oxyhalide is also included as a mixed crystal with the rare earth element halide so that it is not easily oxidatively decomposed when exposed to halogen-based plasma.

In the technique disclosed herein, the halogen-based plasma is typically a plasma generated by using a plasma-generating gas containing a halogen-based gas (halogen compound gas). For example, specifically, fluorogas _{such as SF 6} , CF ₄ , CHF _{3 , ClF 3} , HF and chlorine such as _{Cl 2} , BCl ₃ , HCl used in the dry etching process in the production of semiconductor substrates. A typical example is a plasma generated by using one type of bromine-based gas such as a system gas or HBr alone or a mixture of two or more types. These gases may be used as a mixed gas with an inert gas such as argon (Ar).

The thermal spraying material is typically provided in powder form. Such a powder may be a powder mainly composed of an aggregate of primary particles (may include a form of agglomeration), or is a granulated particle obtained by granulating finer primary particles. It may be configured. However, from the viewpoint of suppressing the oxidation of the thermal spraying material due to thermal spraying, it is preferable that the particles are not granulated particles having a large specific surface area. From the viewpoint of thermal spraying efficiency, the particles constituting the powder are not particularly limited as long as the average particle size is about 100 μm or less, and the lower limit of the average particle size is also not particularly limited. The average particle size of the thermal spraying material can be, for example, 80 μm or less, preferably 60 μm or less, more preferably 50 μm or less, for example, 40 μm or less. The lower limit of the average particle size is also not particularly limited, and when the fluidity of the thermal spraying material is taken into consideration, it can be, for example, 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, for example 20 μm or more. can do.

In the present specification, the "average particle size" of the sprayed material is the particle size (integrated) at an integrated value of 50% in the volume-based particle size distribution measured by a particle size distribution measuring device based on the laser diffraction / scattering method. a _{D 50); 50%} particle size.

Further, the specific surface area of the thermal spraying material is preferably less than ^{0.1 m 2 / g from the viewpoint of preferably suppressing oxidation during thermal spraying.} The specific surface area is preferably at 0.098m ² / g or less, more preferably 0.095 ² / g or less, even more preferably at most 0.093m ² / g. Such a small specific surface area is, for example, a value that cannot be realized by granulated particles having the above-mentioned suitable average particle size.
As the specific surface area of the sprayed material, a value calculated based on the BET method can be adopted. Specifically, for the sprayed material, the gas adsorption amount of the monolayer is obtained from the adsorption isotherm obtained by the gas adsorption method based on the BET method, and the specific surface area is calculated based on the molecular size of the adsorbed gas. Is. The specific surface area of the sprayed material can be measured according to the provisions of JIS Z 8830: 2013 (ISO9277: 2010) "Method for measuring the specific surface area of powder (solid) by gas adsorption". For example, the specific surface area of the sprayed particles can be measured using a surface area measuring device manufactured by Micromeritics, trade name "FlowSorb II 2300".

Similarly, from the viewpoint of preferably suppressing oxidation during thermal spraying and enhancing the plasma erosion resistance and dust generation resistance by making the thermal spray coating more dense, the thermal spray particles constituting the thermal spray material The surface is preferably smooth with no irregularities. For example, for a sprayed material, the cumulative pore volume with a pore radius of 1 μm or less ^{can be 0.1 cm 3} / g or less. The cumulative pore volume may be less ^{0.05cm 3 / g, 0.03cm 3 /} g or less and is preferably not more than 0.02 cm ³ / g. Further, the cumulative pore volume is ^{more preferably 0.01 cm 3} / g or less. Further, it is preferable that the cumulative pore volume of the sprayed material having a pore radius of 1 μm or less is small as described above, because a dense sprayed coating can be formed. It should be noted that such a small cumulative pore volume is a value that cannot be realized by, for example, granulated particles having the above-mentioned suitable average particle size.

The cumulative pore volume of the sprayed material can be calculated based on the mercury intrusion method. The mercury intrusion method utilizes the fact that the surface tension of mercury is large, and the pores from the meso region to the macro region are based on the relationship between the pressure applied to infiltrate the pores of the powder and the amount of mercury injected. This is a method for finding the distribution. The pore distribution measurement based on the mercury intrusion method can be carried out based on, for example, JIS R1655: 2003 (a method for testing the pore size distribution of a molded body by the mercury intrusion method of fine ceramics). For example, the cumulative pore volume of the sprayed material can be measured using a mercury press-fitting porosimeter (Poresizer 9320, manufactured by Shimadzu Corporation).

Further, although not necessarily limited to this, the sprayed particles contained in the sprayed material preferably have an average circularity of 0.5 or more in a plan view from the viewpoint of increasing the fluidity. The average circularity is more preferably 0.55 or more, and particularly preferably 0.6 or more. The upper limit of the average circularity is not particularly limited, but since the thermal spray material disclosed herein is composed of a uniform matrix, the average circularity can typically be less than one.

In this specification, the arithmetic mean value of the circularity in the plan view of the particles constituting 5000 or more sprayed materials obtained by the image analysis method can be adopted as the average circularity. The circularity can be measured as follows. That is, specifically, first, the thermal spray material is dispersed in a dispersion medium for measurement to prepare a sample for measurement. The dispersion medium for measurement is not particularly limited as long as it can suppress the aggregation of the sprayed particles in the sprayed material and adjust the sprayed particles to a dispersed state. In the present embodiment, ion-exchanged water to which a surfactant, polyoxyethylene sorbitan monolaurate, was added at a concentration of 0.1% by mass was used as the dispersion medium for measurement. The proportion of the sprayed material in the measurement sample was 30% by mass or less (30% by mass in this embodiment). By pouring the measurement sample prepared in this way into a measurement container such as a glass cell, a flat sample flow in which the overlap of the sprayed particles is suppressed is formed. By irradiating this sample flow with strobe light and taking an image, a still image of the sprayed particles suspended and flowing in the sample for measurement is acquired. The circularity is calculated by image analysis of the obtained still image of the sprayed particles. The circularity is defined by the following equation: (circularity) = (peripheral length of a circle having the same area as the sprayed particle image) / (peripheral length of the sprayed particle); That is, the circularity is calculated from the projected area per sprayed particle and the perimeter. This circularity is obtained for 5000 or more sprayed particles, and the arithmetic mean value thereof is defined as the average circularity. In the present specification, the above-mentioned average circularity uses a value calculated using a flow-type particle image analyzer (FPIA-2100, manufactured by Sysmex Corporation).

(Manufacturing method of thermal spraying material)
Such a thermal spraying material is not necessarily limited to this, but can be suitably produced, for example, according to the following method for producing a thermal spraying material. FIG. 2 is a flowchart of a method for manufacturing a thermal spraying material as an embodiment.

(S1) Preparation of Raw Material That is, first, a raw material for a thermal spraying material is prepared. As the raw material, for example, powders of rare earth element halides and rare earth element oxides constituting the target mixed crystal can be used. The properties of the powder used as a raw material are not particularly limited, but in order to form a mixed crystal having a uniform composition, for example, the average particle size is preferably as fine as 0.1 μm or more and about 10 μm. The mixing ratio of the rare earth element halide powder and the rare earth element oxide powder can be determined according to the mixing ratio (solid solution ratio) in the target mixed crystal. For example, the desired solid solution ratio may be used as it is as the mixing ratio of the raw material powder. When a powder other than a rare earth element halide or a rare earth element oxide is used as a raw material, the compound used as the raw material and its ratio may be appropriately adjusted so that the desired mixed crystal can be obtained in the stoichiometric composition. ..

(S2) Granulation Next, the prepared raw material powder is granulated into a spherical shape to prepare a granulated powder. By going through this granulation step, it is possible to prevent the formation of angular particles in the subsequent firing step, and a spherical thermal spraying material having excellent fluidity can be preferably obtained. The granulation method is not particularly limited, and various known granulation methods can be adopted. For example, specifically, one or more of the rolling granulation method, the fluidized bed granulation method, the stirring granulation method, the compression granulation method, the extrusion granulation method, the crushing granulation method, the spray-drying method and the like. Can be adopted. The spray-drying method can be preferably adopted from the viewpoint that the raw material powder can be uniformly and uniformly mixed through the dispersion medium with high accuracy. The type of dispersion medium used for spray drying is not particularly limited, and examples thereof include water, lower alcohols (for example, alcohols having 5 or less carbon atoms such as methanol, ethanol, and propanol), and mixed solutions thereof. In addition, a binder can be added to the dispersion medium as needed. Since the granulation conditions depend on the apparatus used, it cannot be said unconditionally, but for example, it is preferable to granulate in the air in a temperature range of 400 ° C. or lower (for example, the drying temperature is about 120 ° C. to 300 ° C.). The size of the granulated particles in the granulated powder may be determined in consideration of the average particle size of the raw material powder and the shrinkage due to the firing step in the next step.

(S3) Firing After that, the granulated powder is calcined. In firing, the individual raw material particles contained in the granulated particles are sintered. During such sintering, the raw material components diffuse with each other to form a mixed crystal. In the thermal spraying material disclosed herein, it is preferable that the raw material particles contained in the granulated particles are sufficiently sintered or melted to be integrated. That is, it is preferable to integrate the granulated bodies to the extent that they can hardly be seen. Examples of the conditions for firing and fusion integration include firing at about 900 ° C. to 1200 ° C. in an inert atmosphere. The firing time is not particularly limited because it depends on the form of the granulated particles, but can be, for example, about 1 hour or more and 24 hours or less (for example, 8 hours or more and 15 hours or less) as a guide. For firing the granulated powder, a general batch firing furnace, a continuous firing furnace, or the like can be used without particular limitation. The firing atmosphere can be, for example, an inert atmosphere so that the blended composition does not change. Examples of the inert atmosphere include a rare gas atmosphere such as argon (Ar) and neon (Ne), a non-oxidizing atmosphere such as _{nitrogen (N 2), and a vacuum atmosphere.} When a batch type firing furnace is used, for example, the atmosphere inside the furnace may be an inert atmosphere. When a continuous firing furnace is used, for example, an inert air stream such as a rare gas or nitrogen is introduced into a region where heating is performed (a region where sintering proceeds) in the firing furnace to perform firing. Just do it. In the production of the thermal spraying material disclosed herein, the air atmosphere and the air atmosphere are aspects that should be avoided because oxidation of the raw material components in the sintering process is unavoidable. Although it is not an essential step, if necessary, steps such as crushing and classifying the fired product may be included after firing. Thereby, the thermal spraying material disclosed herein can be obtained (S4).

In a known general granulated powder, fine particles, which are primary particles, are simply aggregated (bonded by a binder) via a binder, or are sintered to increase the strength. It can be in the given form. Relatively large pores are interposed in the gaps between the fine particles in such a granulated powder, and the surface of the granulated particles has irregularities corresponding to the shape of the fine particles. As described above, in general granulated powder, the presence of relatively large pores between the granulated particles has the meaning of "granulation". For such granulated powder, the cumulative pore volume having a pore diameter of 3 μm or less ^{may exceed 0.1 cm 3} / g.

On the other hand, when the granulated powder is sufficiently sintered and melted and integrated, the fine particles move in order to reduce the surface energy, and the area of the bonding portion (interface) is gradually increased, so that the fine particles become more. Rounded into a stable sphere. At the same time, the pores existing inside the granulated powder are discharged, and densification occurs. As described above, the thermal spraying material disclosed herein may have a reduced pore capacity or disappeared pores as compared with the granulated powder. Then, the surface morphology can be a smooth sphere. When sintering a non-oxide material, oxidation of the material usually occurs. Since the thermal spraying material disclosed herein is integrated by sintering in an inert atmosphere, oxidation is suppressed as described above. As a result, the formation of mixed crystals not found in conventional granulated powder is preferably realized.

[Spray coating]
By spraying the above thermal spraying material, a thermal spray coating can be formed. Since this thermal spray coating is provided on the surface of the base material, it is provided as a member with a thermal spray coating or the like. Hereinafter, the member with the thermal spray coating and the thermal spray coating will be described.
(Base material)
In the member with a thermal spray coating disclosed herein, the base material on which the thermal spray coating is formed is not particularly limited. For example, the material and shape of the base material are not particularly limited as long as the base material is made of a material capable of having a desired resistance to the thermal spraying of the thermal spraying material. Examples of the material constituting such a base material include various metals, metal materials containing semimetals and alloys thereof, various inorganic materials, and the like. Specifically, as the metal material, for example, metal materials such as aluminum, aluminum alloy, iron, steel, copper, copper alloy, nickel, nickel alloy, gold, silver, bismuth, manganese, zinc, zinc alloy; silicon ( Group IV semiconductors such as Si) and germanium (Ge), Group II-VI compound semiconductors such as zinc selenium (ZnSe), cadmium sulfide (CdS) and zinc oxide (ZnO), gallium arsenide (GaAs), indium phosphate (GaAs) Group III-V compound semiconductors such as InP) and gallium nitride (GaN), Group IV compound semiconductors such as silicon carbide (SiC) and silicon germanium (SiGe), chalcopyrite semiconductors such as _{copper, indium and selenium (CuInSe 2), etc.} Semi-metal material; etc. are exemplified. Examples of the inorganic material include a substrate material of calcium fluoride (CaF) and quartz (SiO _{2 ), oxide ceramics such as alumina (Al 2} O ₃ ) and zirconia (ZrO ₂ ), silicon nitride (Si ₃ N ₄ ), and nitride. Examples thereof include nitride ceramics such as boron (BN) and titanium nitride (TiN), and carbide ceramics such as silicon carbide (SiC) and tungsten carbide (WC). Any one of these materials may form a base material, or two or more types may be combined to form a base material. Among the widely used metal materials, steel represented by various SUS materials (which can be so-called stainless steel) having a relatively large coefficient of thermal expansion, heat-resistant alloys represented by Inconel, Inver, and Coval. Preferable examples include low expansion alloys typified by .. Such a base material may be, for example, a member constituting a semiconductor device manufacturing apparatus and may be a member exposed to highly reactive oxygen gas plasma or halogen gas plasma. For example, the above-mentioned silicon carbide (SiC) and the like can be classified into different categories as compound semiconductors, inorganic materials and the like for convenience, but they are the same material.

(Method of forming a thermal spray coating)
The thermal spray coating can be formed by subjecting the thermal spraying material disclosed herein to a thermal spraying apparatus based on a known thermal spraying method. Since this thermal spraying material has a structure that is not easily oxidized by thermal spraying, the thermal spraying method is not particularly limited. Therefore, for example, as shown in FIG. 3, a combination of the above thermal spraying material and various known thermal spraying methods can be adopted without particular limitation. For example, preferably, a flame spraying method, a high-speed frame thermal spraying method, an arc thermal spraying method, a plasma thermal spraying method, a high-speed plasma thermal spraying method, a cold spray thermal spraying method, and other thermal spraying methods such as an explosive thermal spraying method and an aerosol deposition method are adopted. Is exemplified.

As a preferred example, the plasma spraying method is a thermal spraying method in which a plasma flame is used as a thermal spraying heat source for softening or melting a thermal spray material. When an arc is generated between the electrodes and the working gas is turned into plasma by the arc, the plasma flow is ejected from the nozzle as a high-temperature and high-speed plasma jet. The plasma spraying method includes a general coating method for obtaining a thermal spray coating by charging a thermal spray material into the plasma jet, heating and accelerating it, and depositing it on a substrate. The plasma spraying method includes atmospheric plasma spraying (APS), low pressure plasma spraying (LPS), which is performed at a pressure lower than atmospheric pressure, and low pressure plasma spraying (LPS), which is performed at a pressure lower than atmospheric pressure. It may be an embodiment such as high pressure plasma spraying in which plasma spraying is performed in a pressure vessel. The working gas used in plasma spraying is a rare gas typified by argon (Ar) or the like, a reducing gas typified by _{hydrogen (H 2} ) or the like, and a non-oxidizing gas typified by _{nitrogen (N 2) or the like.} Or, a mixed gas of these can be used. According to such plasma spraying, for example, by melting and accelerating the thermal spraying material with a plasma jet of about 5000 ° C. to 10000 ° C., the thermal spraying material collides with the substrate at a speed of about 300 m / s to 600 m / s. Can be allowed to deposit.

Further, as the high-speed frame thermal spraying method, for example, an oxygen-supported high-speed frame (HVOF) thermal spraying method, a worm spray thermal spraying method, an air-supported (HVAF) high-speed frame thermal spraying method, and the like can be considered.
The HVOF thermal spraying method is a type of frame thermal spraying method in which a combustion flame obtained by mixing fuel and oxygen and burning them at high pressure is used as a heat source for thermal spraying. By increasing the pressure in the combustion chamber, a high-speed (possibly supersonic) high-temperature gas flow is ejected from the nozzle while being a continuous combustion flame. The HVOF thermal spraying method includes a general coating method for obtaining a thermal spray coating by putting a thermal spray material into this gas stream, heating and accelerating it, and depositing it on a substrate. According to the HVOF thermal spraying method, for example, by supplying the thermal spray material to a jet of supersonic combustion flame at 2000 ° C. to 3000 ° C., the thermal spray material is softened or melted to a high temperature of 500 m / s to 1000 m / s. It can be deposited by colliding with the substrate at a speed. The fuel used for high-speed flame spraying may be a gas fuel of hydrocarbons such as acetylene, ethylene, propane and propylene, or a liquid fuel such as kerosene and ethanol. Further, it is preferable that the temperature of the supersonic combustion flame is higher as the melting point of the thermal spray material is higher, and from this viewpoint, it is preferable to use gas fuel.

It is also possible to adopt a so-called warm spray thermal spraying method, which is an application of the above HVOF thermal spraying method. The warm spray spraying method is typically a thermal spraying method in which the temperature of the combustion flame is lowered by mixing a cooling gas composed of nitrogen or the like at a temperature of about room temperature with the combustion flame in the above HVOF thermal spraying method. This is a method of forming a thermal spray coating. The thermal spraying material is not limited to a completely melted state, and for example, a material that is partially melted or in a softened state below the melting point can be sprayed. According to this warm spray spraying method, for example, by supplying a thermal spray material to a jet of a supersonic combustion flame at 1000 ° C. to 2000 ° C., the thermal spray material is softened or melted to 500 m / s to 1000 m / s. It can be deposited by colliding with the base material at a high speed of.

The HVAF thermal spraying method is a thermal spraying method in which air is used instead of oxygen as a combustion support gas in the above HVOF thermal spraying method. According to the HVAF thermal spraying method, the thermal spraying temperature can be lowered as compared with the HVOF thermal spraying method. For example, by supplying a sprayed material to a jet of supersonic combustion flame at 1600 ° C to 2000 ° C, the sprayed material is softened or melted to produce sprayed particles at a high speed of 500 m / s to 1000 m / s. Can be deposited by colliding with the base material.

Further, in each of the above-mentioned thermal spraying methods, the thermal spraying material may be supplied in the form of powder or in the form of slurry. The slurry can be prepared by dispersing the powdery thermal spraying material in a dispersion medium. The dispersion medium may be either an aqueous dispersion medium or a non-aqueous dispersion medium. Examples of the aqueous dispersion medium include water and a mixture of water and a water-soluble organic solvent (mixed aqueous solution). As the organic solvent, various organic solvents that can be mixed homogeneously with water can be used, and examples thereof include lower alcohols and lower ketones having 1 to 4 carbon atoms, and more specifically, methanol, ethanol, and the like. One type or two or more types such as n-propyl alcohol and isopropyl alcohol can be mentioned. The non-aqueous solvent typically includes an organic solvent that does not contain water. The organic solvent is not particularly limited, and for example, alcohols such as methanol, ethanol, n-propyl alcohol and isopropyl alcohol, and one kind of organic solvent such as toluene, hexane and kerosene may be used alone or in combination of two or more. It can be used. The content of the thermal spraying material in the slurry, that is, the solid content concentration is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more. In this case, it becomes easy to improve the thickness of the thermal spray coating produced from the thermal spraying slurry per unit time, that is, the thermal spraying efficiency. The content of the thermal spraying material in the slurry is preferably 70% by mass or less, more preferably 60% by mass or less, and further preferably 50% by mass or less. In this case, it becomes easy to obtain a thermal spraying slurry having a required fluidity suitable for good supply to the thermal spraying apparatus, that is, a thermal spraying slurry having a sufficient fluidity for forming a thermal spray coating. In addition, this slurry may contain various additives such as a dispersant and a surfactant for the purpose of preferably maintaining the dispersibility of the thermal spraying material.

Although it is not essential, as shown in FIG. 3, a shroud device may be used in combination in the above thermal spraying method. The shroud device is a cylindrical device for suppressing the oxidation of the thermal spraying material during thermal spraying and the thermal spray coating formed at a higher level. By flowing the shroud gas around the thermal spray jet by this shroud device, the thermal spray material and the thermal spray jet can be shielded from the atmosphere and collide with the surface of the base material. The shroud device can be installed, for example, in the barrel of the thermal spray gun of the thermal spraying device. As the shroud gas, for example, _{an inert gas typified by argon (Ar), nitrogen (N 2} ) or the like can be used. Thereby, for example, overheating and oxidation of the thermal spraying material can be suppressed, and a dense thermal spray coating having a low oxygen content can be obtained.

(Spray coating)
The thermal spray coating disclosed herein is formed by spraying the above-mentioned thermal spraying material onto, for example, the surface of an arbitrary base material. Therefore, such a sprayed coating contains, for example, a rare earth element (RE), an oxygen (O) and a halogen element (X) as constituent elements. Further, the thermal spraying material disclosed herein may contain a mixed crystal of an oxyhalide of a rare earth element and a halide of a rare earth element as described above. In a preferred embodiment of the above-mentioned thermal spraying material, it is a powder composed of particles having a smooth surface, and such a thermal spraying material is difficult to be oxidized even when it is subjected to thermal spraying, and the halogen element volatilizes due to oxidative decomposition. It is suppressed. As a result, the thermal spray coating obtained by spraying this thermal spray material can have a dense structure. For example, the porosity of the thermal spray coating obtained by using a conventional thermal spraying material composed of a rare earth element oxyhalide containing no mixed crystals exceeds 5.5% (for example, 5.8% or more). , The sprayed coating disclosed herein has a porosity reduced to, for example, 5.5% or less. The porosity of the sprayed coating can be, for example, 5% or less, preferably 4.5% or less, more preferably 4% or less, particularly preferably 3.5% or less, for example 3 It may be less than or equal to%. As a result, even when exposed to halogen-based plasma, a thermal spray coating in which the generation of fine particles is suppressed is realized.

The thermal spray coating disclosed herein can be formed in a state in which the volatilization of halogen elements is suppressed from the thermal spraying material as described above, and the composition ratios of rare earth elements, oxygen, and halogen elements are generally maintained. Therefore, the content of the halogen element is increased as compared with the thermal spray coating obtained from the conventional thermal spraying material composed of the rare earth element oxyhalide. The ratio of the halogen element to the total of the rare earth element, oxygen, and halogen element in the sprayed coating is preferably 30 atomic% or more, and more preferably 35 atomic% or more. However, if the sprayed coating contains an excessive amount of halogen elements, the composition of the sprayed coating becomes closer to the rare earth element halide than to the rare earth element oxyhalide, which is not preferable because the dust generation resistance may be lowered. Therefore, the ratio of the halogen element to the total of the rare earth element, oxygen, and halogen element in the sprayed coating is preferably 55 atomic% or less, more preferably 50 atomic% or less, for example, 45 atomic% or less.

Further, in the thermal spray coating thus obtained, oxidation of the thermal spraying material due to thermal spraying is sufficiently suppressed. Therefore, the above-mentioned rare earth element (RE), oxygen (O) and halogen element (X) can exist as a rare earth element oxyhalide. For example, the thermal spray coating is configured as a coating containing a rare earth element oxyhalide (RE-OX) as a main component.
Here, the "main component" means that the component has the highest content among the components constituting the thermal spray coating. Specifically, for example, it means that the component occupies 50% by mass or more of the entire sprayed coating, and preferably 75% by mass or more, for example, 80% by mass or more. Since the rare earth element oxyhalide is the same as that in the above-mentioned thermal spraying material, detailed description thereof will be omitted.
Although the detailed mechanism is not clear, the rare earth element oxyhalide is excellent in dust generation resistance and plasma erosion resistance, particularly dust generation resistance to halogen-based plasma. Therefore, the thermal spray coating containing the rare earth element oxyhalide as a main component can be extremely excellent in dust generation resistance.

In a more preferred embodiment, the sprayed coating disclosed herein may contain a mixed crystal of a rare earth element oxyhalide and a rare earth element halide. That is, although the solid solution ratio of the rare earth element halide may be lowered in the mixed crystal in the thermal spraying material, the content as the mixed crystal is maintained. The composition of the mixed crystal and the proportion in the coating film are not particularly limited. For example, the proportion of mixed crystals in the sprayed coating can be, for example, 5% by mass or more, 10% by mass or more, preferably 15% by mass or more, and for example, 20% by mass or more. .. This provides a sprayed coating that is even more dense and has excellent plasma erosion resistance and dust generation resistance.

Further, the thermal spray coating disclosed herein can be realized as substantially free of rare earth element halides. When the rare earth element halide is contained in the sprayed coating, the portion where the rare earth element halide is present is easily oxidized when the sprayed coating is exposed to, for example, oxygen plasma. When a rare earth element oxide is formed by oxidation of a rare earth element halide, this rare earth element oxide can form a partially altered layer. Since the altered layer portion (rare earth element oxide) is relatively hard but brittle, when exposed to a plasma environment by dry etching or the like, the altered layer portion may peel off and fine particles may be generated (dust).
In contrast, the sprayed coatings disclosed herein are substantially free of rare earth element halides. Therefore, the generation of fine particles when exposed to plasma is suppressed, and the plasma erosion resistance and dust generation resistance can be extremely excellent.

The altered layer formed by exposing the thermal spray coating to halogen-based plasma will be described. For example, Figure 4 is a thermal spray coating (e.g., _Y 2 _{O 3} sprayed coating) exposed to fluorine plasma (A1) before and (B1) TEM image of a cross-section of the post. As is clear from the figure, in the sprayed coating after being exposed to the fluorine plasma, a clear modulation is observed in the crystal structure in the vicinity of the surface (a region of about 50 nm from the surface). The formation of such an altered layer is remarkable when the composition of the sprayed coating is a rare earth element oxide. This phenomenon is considered to be due to the following reasons. That is, for example, (A2) Y ₂ O ₃ has a volume of 22.7 cm ³ _{/ mol per mole, and fluoride (YF 3} ) is formed by exposure to highly reactive fluorine plasma. (B2) The _{volume of YF 3} per mole is 37.0 cm ³ / mol, which is 1.62 times that of _{Y 2} O _3. That is, it is considered that as a result of the volume expansion by the halogen-based plasma irradiation, the coating structure of the sprayed coating is broken at the crystal level to become porous, and fine particles are easily generated by the subsequent irradiation with further plasma.

Further, as a more preferable embodiment, the sprayed coating is also provided so as to be substantially free of the oxides of the above rare earth elements. As described above, rare earth oxides are relatively hard but brittle, so that fine particles can be generated when exposed to a plasma environment by the following dry etching or the like. Therefore, since the thermal spray coating disclosed herein does not substantially contain this rare earth element oxide, it can be extremely excellent in dust generation resistance.

It should be noted that in a dry etching apparatus for manufacturing a semiconductor device, reduction in particles is required. Factors for generating the particles include peeling of the reaction product adhering to the inside of the vacuum chamber, and deterioration of the chamber and its protective film (which may be a thermal spray coating) due to the use of halogen gas plasma or oxygen gas plasma. .. Therefore, in the conventional semiconductor device manufacturing apparatus, the part exposed to plasma is replaced every predetermined operation time (plasma exposure time) determined according to its plasma erosion resistance characteristics.
The plasma erosion resistance characteristics of the sprayed coating have been conventionally evaluated by the amount of consumption of the sprayed coating due to plasma irradiation (for example, the amount of etching, the etching rate, etc.). As an example, the amount of the thermal spray coating obtained from the thermal spraying materials having the following four compositions is generally increased in the following order, and the thermal spray coating of _{alumina (Al 2} O _{3) is plasma.} most eroded easily, Y ₂ O ₃ sprayed coating is rated as resistant to most eroded by plasma. Alumina, is in the oxide are known to be the most rigid, Y 2 _{O 3, YOF,} spray coating formed of the thermal spraying material YF ₃ is higher plasma resistance than either alumina sprayed coating It can be said that it has erosion characteristics.
Y ₂ O ₃ <YOF <YF ₃ << Al ₂ O ₃

On the other hand, the larger the particle size of the particles, the more problematic it may be. However, in recent years when the processing accuracy has been refined, the generation of particles having a particle size of 0.2 μm or less (less than 0.2 μm, for example, 0.1 μm or less) is severe. There is a need to limit. Here, the particles having a size of 0.2 μm or less have a feature that the volume of one particle itself is small, but the number can be easily increased. Therefore, the generation of particles of 0.2 μm or less can be considered as “dust generation” in distinction from the conventional relatively large particles. According to the study by the present inventors, the number and size of particles emitted from the sprayed coating have a great influence on the composition and structure of the sprayed coating, especially the composition, not on the operating time (plasma exposure time) of the semiconductor device manufacturing apparatus. It is known that it will be done. In other words, when the sprayed coating is exposed to halogen gas plasma or oxygen gas plasma, the composition of the sprayed coating itself changes (altered), and the coating structure also changes, inducing the generation of finer particles (that is, dust generation). It is thought that it will be easier to do. It has been confirmed that the dust generation property of such a sprayed coating generally increases in the following order depending on the composition of the sprayed coating as an example. That is, the _{thermal spray coating formed from Y 2} O ₃ tends to generate particles of 0.2 μm or less, and is evaluated to be inferior in dust generation resistance.
YOF <YF ₃ <Y ₂ O ₃

In contrast, thermal spray material disclosed herein, since it contains a mixed crystal of a rare earth element halides (e.g. YF ₃₎ and rare earth oxyhalide (e.g. _Y 5 _O 4 _{F 7),} from YF ₃ It is less likely to be oxidized by thermal spraying than the thermal spraying material made of YOF or the thermal spraying material made of YOF. As a result, the thermal spray coating formed from the thermal spraying material disclosed herein has high dust generation resistance such as _{a rare earth element halide (for example, YF 3} ) and a rare earth element oxyhalide (for example, Y ₅ O ₄ F _7). It may have a composition. Therefore, by using the thermal spraying material disclosed herein, it is possible to form a thermal spraying film having extremely excellent both plasma erosion characteristics and dust generation resistance. According to the conventional thermal spray coating, particles of 0.2 μm or more could be generated, but by performing thermal spraying using the thermal spraying material disclosed here, for example, in the current dry etching environment, about 0. The formation of an altered layer that causes the generation of coarse particles of 2 μm or more is suppressed. When the sprayed coating disclosed herein is corroded in a dry etching environment, the generated particles are mainly due to a particulate alteration layer having a size of about 0.2 μm or less (typically 0.1 μm or less). This is because it is composed and its number is also suppressed. Therefore, the thermal spray coating disclosed herein is, for example, about 0.2 μm or less (for example, 0.1 μm or less, typically 0.06 μm or less, preferably 19 nm or less, more preferably 5 nm or less, most preferably 1 nm or less. ) Particles are suppressed. For example, the number of these particles generated is substantially suppressed to zero.

The dust generation resistance of such a sprayed coating can be evaluated by, for example, the number of particles generated when the sprayed coating is exposed to a predetermined plasma environment. In general dry etching, an etching gas is introduced into a vacuum vessel (chamber), and the etching gas is excited by a high frequency or a microwave to generate plasma to generate radicals and ions. Radicals and ions generated by this plasma are reacted with an object to be etched (typically a silicon wafer), and the reaction product is exhausted as a volatile gas to the outside by a vacuum exhaust system, whereby the object to be etched Can be finely processed. For example, in an actual parallel plate type RIE (reactive ion etching) apparatus, a pair of parallel plate electrodes are installed in an etching chamber. Then, a high frequency is applied to one of the electrodes to generate plasma, and a wafer is placed on this electrode to perform etching. Plasma is generated in a pressure band of about 10 mTorr or more and 200 mTorr or less. As the etching gas, as described above, various halogen gases, oxygen gases, and inert gases can be considered. When evaluating the plasma erosion resistance of the sprayed coating, a mixed gas containing halogen gas and oxygen gas (for example, a mixed gas containing argon, tetrafluorocarbon and oxygen in a predetermined volume ratio) is used as the etching gas. Is preferable. The flow rate of the etching gas is preferably, for example, about 0.1 L / min or more and 2 L / min or less.

Then, by measuring the number of particles generated after placing the sprayed coating in such a plasma environment for a predetermined time (for example, the time for processing 2000 semiconductor substrates (silicon wafers, etc.)), the plasma resistant coating is resistant to plasma. The erosion property can be suitably evaluated. Here, in order to realize a high level of quality control, for example, particles having a diameter of 0.06 μm or more can be measured, but the particles can be appropriately changed according to the required quality. .. Then, for example, the plasma erosion resistance is evaluated by calculating how many particles of such a size are deposited per unit area of the semiconductor substrate and obtaining the number of particles generated (pieces / cm ^2). Can be done.
Regarding a preferable aspect of the thermal spray coating disclosed herein, it can be recognized that the ^{number of such particles generated can be suppressed to about 15 particles / cm 2 or less.} For example, the number of particles generated under the conditions specified below ^{can be 15 particles / cm 2} or less. Such a configuration is preferable because a thermal spray coating having reliably improved plasma erosion resistance can be realized.

[Particle generation count condition]
A 70 mm × 50 mm thermal spray coating is installed on the upper electrode of the parallel plate type plasma etching apparatus. In addition, a substrate to be plasma-processed having a diameter of 300 mm is installed on the stage. Then, first, in order to imitate the state of the sprayed coating after long-term use, a dummy run for a total of 100 hours is performed in which 2000 substrates (silicon wafers) are subjected to plasma dry etching treatment. The plasma generation conditions are pressure: 13.3 Pa (100 mTorr), etching gas: argon, a mixed gas of carbon tetrafluoride and oxygen, and an applied voltage of 13.56 MHz, 4000 W. After that, a substrate (silicon wafer) for a measurement monitor is placed on the stage, and plasma is generated for 30 seconds under the same conditions as above. Then, before and after the above plasma treatment, the number of particles having a diameter of 0.06 μm or more deposited on the substrate for the measurement monitor is counted. At this time, the value obtained by dividing the number of counted particles by the area of the substrate may be used for evaluation as the ^{number of generated particles (pieces / cm 2).} At this time, the etching gas is a mixed gas containing argon, carbon tetrafluoride, and oxygen. The flow rate of the etching gas is, for example, 1 L / min.

Hereinafter, some examples of the present invention will be described, but the present invention is not intended to be limited to those shown in such examples.

[Embodiment 1]
[Material for thermal spraying]
(Reference example)
A thermal spraying material of a reference example was obtained according to the disclosure of Example 10 of paragraphs 0045 to 0051 of Patent Document 1 (International Publication No. 2014/002580). Specifically, first, the wet-synthesized yttrium fluoride was calcined at 1125 ° C. for 12 hours in an air atmosphere, and then granulated and dried by using a spray dryer to obtain a granulated product. Next, the obtained granules were placed in an alumina container and fired in an electric furnace at 600 ° C. for 12 hours in an air atmosphere to obtain a thermal spraying material of a reference example in the form of granulated granules.

(Examples 1 and 2)
_{As a thermal spraying material, granular powders of yttrium oxide (Y 2} O ₃ ) and yttrium fluoride (YF ₃ ), which are generally used as a protective film for members in semiconductor device manufacturing equipment, were prepared, and Example 1 respectively. It was used as a material for thermal spraying of ~ 2. These materials, using a powder having an average particle size of about 3 [mu] m Y ₂ O ₃ or YF ₃ as a raw material, after dispersed in a dispersion medium together with the resin binder at a solids concentration of 50 wt%, of the rotary disc spray It was prepared by granulating with a dry granulator and sintering at 1000 ° C. in a non-oxidizing atmosphere.

(Examples 3-4)
Granular powders of yttrium oxyfluoride having the compositions of YOF (Y ₁ O ₁ F ₁ ) and Y ₅ O ₄ F ₇ were prepared and used as the thermal spraying materials of Examples 3 to 4, respectively. For these spray material has an average particle diameter using a powder of _Y 2 _{O 3} and YF ₃ to about 3μm as a raw material, were respectively compounded them as YF ₃ is a ratio of about 40 mol% and about 50 mol% After that, it was prepared by granulating and sintering under the same conditions as in Examples 1 and 2.

(Example 5)
A powder of yttrium oxyfluoride having a composition of Y ₅ O ₄ F ₇ (not in the form of granules) was prepared and used as a thermal spraying material of Example 5. This thermal spraying material was prepared by the following procedure. _{That is, first, powders of Y 2} O ₃ and YF ₃ having an average particle size of about 3 μm are used as raw materials, and these are _{mixed so that YF 3} has a ratio of about 50 mol%, and dispersed in a dispersion medium together with a resin binder. To prepare a slurry. Next, this slurry was granulated by a spray-drying method using an ultrasonic nebulizer, and then sufficiently melted or sintered at 1000 ° C. in a non-oxidizing atmosphere to prepare the slurry.

(Examples 6 to 8)
Then, prepare a powder composed of a mixed crystal of Y ₅ O ₄ F ₇ and YF ₃ having different compositions of the solid solution rate (not granular.), Was spraying material of Examples 6-8 respectively .. For these spray material is a powder having an average particle size of about 3μm of _Y 2 _{O 3} and YF ₃ used as a raw material, and blended them as YF ₃ becomes a predetermined ratio greater than about 60 mol%, the resin A slurry was prepared by dispersing in a dispersion medium together with a binder. After that, it was prepared by granulating under the same conditions as in Example 5 above and melting or sintering.

(Example 6 * to 8 *)
For reference, the firing of the granulated powder in Examples 6 to 8 above is performed in a non-oxidizing atmosphere at 1000 ° C. to the extent that the granulated particles are sintered, so that the granulated powder is sprayed in the form of granulated powder. Materials for use were prepared.

The physical characteristics of these thermal spraying materials were investigated and shown in Table 2 below.

In the "Composition" column of "Thermal spraying material" in Table 2, the crystal phase detected as a result of powder X-ray diffraction analysis for each thermal spraying material or the estimated rough composition was shown. In the same column, "Y2O3" is composed of a phase composed of yttrium oxide, "YF3" is composed of a phase composed of yttrium fluoride, and "Y5O4F7" is composed of yttrium oxyfluoride having a chemical composition represented by _{Y 5} O ₄ F _7. Indicates that a phase has been detected. Further, "Y5O4F7 / YF3" indicates that a mixed crystal of yttrium oxyfluoride and yttrium fluoride was obtained. For reference, the result of XRD analysis of the thermal spraying material of Example 8 is adopted as the XRD pattern of the powder (c) in FIG.

For this analysis, an X-ray diffraction analyzer (Ultima IV, manufactured by RIGAKU) was used, CuKα rays (voltage 20 kV, current 10 mA) were used as the X-ray source, and the scanning range was 2θ = 10 ° to 70 °. The measurement was performed with a scan speed of 10 ° / min and a sampling width of 0.01 °. The divergence slit was adjusted to 1 °, the divergence vertical limiting slit was adjusted to 10 mm, the scattering slit was adjusted to 1/6 °, the light receiving slit was adjusted to 0.15 mm, and the offset angle was adjusted to 0 °.

In the "Element ratio" column, the concentration (atom (%)) of yttrium (Y), oxygen (O), and fluorine (F) in each material for spraying is shown in the EDX analyzer (manufactured by HORIBA, Ltd., EX). The results of measurement using −250SE) are shown.

The column of "molar ratio / solute rate", _Y 5 _O 4 _{F 7} phase contained in the thermal spraying materials, YOF phase, the proportion of the YF ₃ phase and _Y 2 _{O 3} phase, the sum of the total 100 mol% It was shown to be. The ratio of each phase was calculated from the ratio of the peak heights of the maximum peaks of each crystal phase in the X-ray diffraction pattern. Note that the spraying material of Examples 6-8, the rate of solid solution and _Y 5 _O 4 _{F 7} phase and YF ₃ phase in the mixed crystal, both total showed calculates 100 mol%.

In the "particle size distribution" column, the results of volume-based particle size distribution measurement of each material for spraying, which are measured using a laser diffraction / scattering particle size distribution measuring device (manufactured by HORIBA, LA-300), are shown. .. In the column of "<20", the volume ratio (%) of the particles having a particle size of 20 μm or less is shown.
In the columns of "D10", "D50", and "D90", the cumulative 10% particle size, the cumulative 50% particle size (average particle size), and the cumulative 90% particle size based on the obtained particle size distribution are shown, respectively.

In the "Cumulative pore volume" column, the pore distribution characteristics of each sprayed material are measured, and the cumulative pore volume of pores with a pore radius of 1 μm or less calculated from the results is measured by a mercury intrusion porosimeter (mercury press-fitting porosimeter). The results of measurement using a Pore Sizer 9320) manufactured by Shimadzu Corporation are shown.

In the column of "powder type", "granule" is shown when each thermal spraying material is granule, and "melt" is shown when granulated and then sintered and fused and integrated.

(Formation of thermal spray coating)
In addition, No. By using the thermal spraying materials 1 to 9 and spraying using the plasma sprayer shown in Table 2, No. A member with a thermal spray coating having 1 to 9-2 thermal spray coatings was produced. The thermal spraying conditions were as follows.
That is, first, as a base material to be sprayed, a plate material (70 mm × 50 mm × 2.3 mm) made of an aluminum alloy (Al6061) is prepared and blasted with a brown alumina abrasive (A # 40). Using. Plasma spraying was performed using a commercially available plasma spraying device "SG-100" (manufactured by Praxair Surface Technologies). The plasma generation conditions for thermal spraying using SG-100 are that argon gas 50 psi (0.34 MPa) and helium gas 50 psi (0.34 MPa) are used as the thermal spray gas (plasma working gas), the voltage is 37.0 V, and the current is 900 A. Plasma was generated under the conditions. A powder feeder (Praxair Surface Technologies, Model 1264) was used to supply the thermal spraying material to the thermal spraying apparatus, and the thermal spraying material was supplied to the thermal spraying apparatus at a speed of 20 g / min, and the thickness was 200 μm. A sprayed coating was formed. The movement speed of the thermal spray gun was 24 m / min, and the thermal spray distance was 90 mm.

(Spray coating)
The characteristics with the sprayed coating thus obtained were investigated and shown in Table 2.
In the column of "porosity" in Table 2, the measurement results of the porosity of each sprayed coating are shown. The porosity was measured as follows. That is, the sprayed coating was cut at a plane orthogonal to the surface of the base material, the obtained cross section was resin-filled and polished, and then a cross-sectional image was taken using a digital microscope (manufactured by OMRON Corporation, VC-7700). .. Then, by analyzing this image using image analysis software (Image Pro manufactured by Nippon Roper Co., Ltd.), the area of the pore portion in the cross-sectional image is specified, and the area of the pore portion occupies the entire cross section. Was obtained by calculating. For reference, the results of observing the cross sections of the thermal spray coatings obtained by spraying the thermal spraying materials of Examples 5 and 8 by SEM are shown in FIGS. 5 and 6, respectively.

In the column of "presence or absence of unmelted particles", the result of observing the thermal spray coating with a scanning electron microscope (SEM) and observing whether or not the thermal spraying material remains in the thermal spray coating in an unmelted state is shown. rice field. "Yes" indicates that unmelted particles were confirmed in the sprayed coating, and "No" indicates that no unmelted particles were confirmed in the sprayed coating. For reference, FIG. 7 shows the results of observing the thermal spray coating obtained by spraying the thermal spraying material of the reference example.
In the "Element ratio" column, the results of measuring the concentrations (atoms (%)) of yttrium (Y), oxygen (O), and fluorine (F) in each sprayed coating using the same EDX analyzer as above are shown. Indicated.

In the "XRD intensity ratio" column, the intensity of the main peak of each crystal phase detected in the diffraction pattern obtained as a result of powder X-ray diffraction analysis for each sprayed coating was set to 100 as the highest main peak intensity. It is shown as a relative value. For reference, the main peak of each crystal phase is _{29.157 ° for Y 2} O ₃ , 27.881 ° for YF ₃ , 28.064 ° for YOF, and Y ₅ O ₄ F ₇ . Detected at 28.114 °. Note that the "YOF system" has the same crystal structure as YOF and _Y 5 _O 4 _{F 7,} unknown compounds of specific composition (i.e., Y, O, can not be identified element ratio F compound) The intensity ratio of the main peak of the pattern is shown.

The column of "Y3d orbital" shows the result of measuring the binding energy of the 3d orbital of the element Y in each sprayed coating using the same XPS analyzer as above.

In the "Plastic resistance" column, the results of plasma erosion resistance evaluation for each sprayed film are shown. Specifically, the result of measuring the reduction amount (etching amount) of the thermal spray coating film thickness when the thermal spray coating was exposed to halogen-based plasma for 10 hours was shown. That is, first, the surface of the sprayed coating of the member with the sprayed coating prepared above was mirror-polished using colloidal silica having an average particle diameter of 0.06 μm. Then, the member with the thermal spray coating was installed on the member corresponding to the upper electrode in the chamber of the parallel plate type semiconductor device manufacturing apparatus so that the polished surface was exposed. Then, a silicon wafer having a diameter of 300 mm was placed on the stage in the chamber, and a dummy run for performing plasma dry etching on 2000 silicon wafers was carried out for 100 hours. The plasma in the etching process keeps the pressure in the chamber at 13.3 Pa and _{contains an etching gas containing argon (Ar), carbon tetrafluoride (CF 4} ) and oxygen (O) in a predetermined ratio at a flow rate of 1 L / min. It was generated by applying a high frequency power of 1500 W at 13.56 MHz while supplying with. After that, a silicon wafer with a diameter of 300 mm for particle counting was placed on the stage in the chamber, and the amount of decrease in the film thickness of the sprayed coating when plasma was generated for 10 hours under the same conditions as above is shown in μm units. rice field.

In the column of "dust generation property", the result of evaluating the number of particles generated from the sprayed coating when the sprayed coating was exposed to halogen-based plasma for 1 hour was shown. Evaluation results when the number of particles generated when plasma etching was performed on each sprayed coating under the same conditions as above was measured using Surfscan SP5 instead of Surfscan SP2, a wafer surface inspection device manufactured by KLA-Tencor. Is shown. The Surfscan SP5 can detect particles having a diameter of 19 nm or more, and the number of particles [2] shows the result when even finer particles deposited on the silicon wafer are measured. It has been confirmed that the number of particles generated is approximately saturated about 30 minutes after plasma exposure, but in this example, the exposure time is set to 1 hour in order to eliminate variations. When counting the total number of particles, the number of particles on the silicon wafer is counted before and after plasma etching for 30 seconds, and the difference is the number of particles (total number) generated from the thermal spray coating after plasma irradiation and deposited on the silicon wafer. And said.

Described in the column of the number of particles [2],
"A *" indicates the case where the number of particles (relative value) is 1 or less.
“A” indicates a case where the number of particles exceeds 1 and is 5 or less.
"B" indicates a case where the number of particles exceeds 5 and is 15 or less.
"C" indicates the case where the number of the particles is more than 15 and 100 or less.
“D” indicates a case where the number of the particles exceeds 100.

In the column of "altered layer", the result of confirming whether or not the altered layer was formed on the surface of the sprayed film when the above-mentioned plasma was irradiated to each sprayed film was shown. The formation of the altered layer was confirmed by observing the cross section of the sprayed membrane with a transmission electron microscope (TEM). In the TEM observation, in the vicinity of the surface of the cross section of the sprayed coating, the portion where the contrast was clearly different from the surroundings and lacked denseness was defined as the altered layer. When the altered layer is formed, the average value when the thickness (dimensions) of the altered layer is measured at 5 points in the TEM image of the altered layer is taken as the average thickness of the altered layer, and the result is "altered" in Table 2. I filled in the "Layer" column.

(evaluation)
As is clear from the reference examples in Table 2, the granular thermal spraying material produced by firing in the air had a firing temperature as low as about 900 ° C. in order to avoid excessive oxidation, so that the composition of YF was the starting material. It was found that YOF was contained only slightly at _{3 as it was.} FIG. 7 is an observation image showing a part of the surface state of the thermal spray coating obtained by spraying the thermal spraying material of the reference example. As shown in FIG. 7, it was confirmed that the granular thermal spraying material was not sufficiently melted in the thermal spray frame and formed a thermal spray coating in an unmelted state. It was also found that the sprayed coating of the reference example had a porosity of 13%, which was the highest among all the cases. It is considered that this is because the thermal spraying material is granules containing a large amount of fluorine, so that a large amount of fluorine is volatilized during the thermal spraying, which hinders the formation of a dense thermal spray coating. Further, it is considered that the heat was not sufficiently transferred to the inside of the granulated particles during the thermal spraying because the material for thermal spraying was granules, and a film was formed in the central portion as the granules. Therefore, in the reference example, although the fluorine content in the thermal spray coating is relatively high, a _{large amount of Y 2} O ₃ is formed due to the oxidation of _{YF 3} , and the thermal spray coating contains as much as 15% of _{Y 2} O _3. I understood it. As a result, it was found that the sprayed coating of the reference example had low plasma erosion resistance due to its high porosity and was easily etched by being exposed to plasma. At the same time, the thermal spray coating of Reference Example is affected layer formed by being exposed to the plasma since it contains a large amount of Y ₂ O _3, it was found that the higher the dusting.

On the other hand, as is clear from the result of Example 1, the thermal spraying film formed by spraying a thermal spraying material consisting only of _{Y 2} O _{3 (yttrium oxide) is essentially composed of only Y 2} O ₃ and is sprayed. It was found that no further oxidative decomposition of Y ₂ O _{3 was observed.} That spray coating Example 1 was found to be composed of only Y ₂ O ₃ phase. The thermal spray coating of Example 1 had a relatively low porosity of 4%, but the thermal spraying material in the form of granules was not completely melted by thermal spraying, and a granular structure was observed in a part of the thermal spray coating. It turned out to be. It is considered that this is because only the surface of the granules melted and adhered to the base material during thermal spraying, but the inside of the granules did not melt and the fine particles constituting the granules remained in the coating film.

It was found that the sprayed coating of Example 1 had the smallest etching amount among all the examples when exposed to plasma for 10 hours, and was excellent in plasma erosion resistance. However, the amount of particles having a diameter of 19 nm or more generated when exposed to plasma for 1 hour was the largest among all the cases. Further, it was found that the surface of the sprayed coating of Example 1 was significantly altered by being exposed to plasma for 1 hour, and a plurality of altered layers having a size of about 50 nm were formed. The size of this altered layer is remarkably large in all cases, and a correlation can be seen with the amount of particles generated. Therefore, spray coating Y ₂ O ₃ composition in terms of耐発Dust was confirmed that most inferior in all cases.

Further, from the results of Example 2, _{it was found that the thermal spraying material containing yttrium fluoride (YF 3} ) was partially oxidized by thermal spraying to form yttrium fluoride and yttrium oxyfluoride in the thermal spray coating. rice field. However, the yttrium fluoride and yttrium oxyfluoride were found at a position where the binding energy of the 3d orbital of Y was higher than 160 eV from the results of XPS analysis, and it was found that no mixed crystals were formed in the sprayed coating. ..
The thermal spray coating of Example 2 had a relatively low porosity of 3%, but it was found that a structure made of unmelted thermal spraying material in a granular state was observed in a part of the thermal spray coating. It was found that the thermal spray coating of Example 2 was the worst in all cases in terms of plasma erosion resistance. Further, it was found that the surface of the sprayed coating of Example 2 was altered by exposure to plasma for 1 hour to form an altered layer of about 10 nm. The dimensions of the altered layer is larger second only to Example 1, as a result, the thermal spray coating of YF ₃ composition be slightly inferior to耐発Dust was confirmed.

The thermal spraying material of Example 3 is a granule containing yttrium oxyfluoride whose composition is represented by YOF. It was confirmed that this thermal spraying material produces yttrium oxide in the thermal spray coating at a high rate of 50% or more by thermal spraying. Further, it was confirmed that in this thermal spraying material, fluorine in the oxyfluoride was volatilized by thermal spraying, and the porosity of the obtained thermal spray coating became an extremely high value of 9%. It is considered that such a tendency is promoted by the fact that the thermal spraying material is granules, has a high specific surface area, and is easily oxidized during thermal spraying. Further, it was found that the plasma erosion resistance of the thermal spray coating of Example 3 was inferior to that of Example 1, but superior to that of Example 2. Further, although the thermal spray coating of Example 3 contains YOF having excellent dust generation resistance, the porosity is high, so that the state of formation of the altered layer and the dust generation resistance are about the same as in Example 2. It turned out to be.

The thermal spraying material of Example 4 is a granule containing yttrium oxyfluoride _{having a composition of Y 5} O ₄ F _7. Since the thermal spraying material of Example 4 is granular, it was confirmed that even if it is heated in the thermal spraying frame, it can remain in the thermal spray coating in an unmelted state. This also applies to the thermal spray coatings obtained from the above-mentioned reference examples and the thermal spray materials of Examples 1 to 3 regardless of the composition. It was confirmed that in _{this thermal spraying material, although Y 5} O ₄ F ₇ remained in the thermal spray coating by thermal spraying, most of it was oxidized to YOF and some to Y ₂ O _3. Furthermore, since the thermal spraying material itself contains fluorine in a high proportion and is volatilized during thermal spraying, it was confirmed that the porosity of the obtained thermal spray coating is 10%, which is higher than that of Example 3. .. Since the thermal spray coating of Example 4 _{did not contain the YF 3-} phase, the plasma erosion resistance was about the same as that of Example 3. _{However, since the proportions of YOF and Y 5} O ₄ F ₇ were higher than in Example 3, only a small alteration layer of 5 nm was observed, and it was found that the alteration layer was not easily altered by plasma. However, probably because the sprayed coating of Example 4 had a high porosity of 10%, the dust generation resistance was about the same as that of C and Examples 2 and 3.

The thermal spraying material of Example 5 is a yttrium oxyfluoride powder having a _{composition of Y 5} O ₄ F _7. It was confirmed that this thermal spraying material was composed _{of a single phase of Y 5} O ₄ F ₇ and did not form mixed crystals, but the cumulative pore volume was remarkably low because the raw material powder was melt-integrated. As a result, it was found that a thermal spray coating containing a high proportion of _{Y 5} O ₄ F _{7 phase and YOF phase can be formed.} Also, even though the composition of the thermal spraying materials are the same as Example 4, the amount of YOF formed in the thermal spray coating is increased, the ratio of oxidized to Y ₂ O ₃ was confirmed to decrease .. It was also found that the porosity of the sprayed coating was slightly reduced to 8% (see FIG. 5). It was found that the thermal spray coating of Example 5 had a plasma erosion resistance property as large as that of Example 2, but the size of the altered layer was as small as 5 nm, and the dust generation resistance was suppressed as low as B.

The thermal spraying material of Example 6 is a powder of yttrium oxyfluoride. It was confirmed that the cumulative pore volume of this thermal spraying material was extremely low because the raw material powder was melted and integrated. As a result of XRD analysis, thermal spray material of Example 6 _was found to contain a mixed crystal of Y ₅ O 4 _{F 7} and YF _3. Rate of solid solution of _Y 5 _O 4 _{F 7} and YF ₃ in the mixed crystal is 80: it was confirmed that 20. In the thermal spraying material of Example 6, it was found that _{most of the thermal spray coating was formed by Y 5} O ₄ F _7. Further, it was confirmed that although the sprayed coating _{contained a small amount of Y 2} O ₃ , the others were YOF and were generally composed of yttrium oxyfluoride. In addition, as a result of XPS analysis, it was found that the sprayed coating itself of Example 6 also contained mixed crystals. It was found that this sprayed coating had a porosity of 5%, which was significantly lower, and a dense sprayed coating was formed because the volatilization of fluorine by thermal spraying was suppressed as compared with Examples 4 and 5. This spray material of Example 6 comprises a mixed crystal, oxidative decomposition of the Y ₂ O ₃ is considered to be due to a suppressed. The thermal spray coating of Example 6 had the same plasma erosion resistance as in Examples 3 to 4, but no alteration layer was observed even when irradiated with plasma, and the dust generation resistance was as small as A. It was found that the amount of generated particles can be suppressed to an extremely low level.

The thermal spraying materials of Examples 7 and 8 are powders of yttrium oxyfluoride. These thermal spraying materials also have a significantly low cumulative pore volume because the raw material powder is melt-integrated. Results of XRD analysis, these spraying material _comprises mixed crystals of Y ₅ O 4 _{F 7} and YF _3, the solid solution ratio of _Y 5 _O 4 _{F 7} and YF ₃ in mixed crystals of Example 7 It was confirmed that the ratio was 56:44 for the thermal spraying material and 28:72 for the thermal spraying material of Example 8. From the comparison of Examples 6 to 8, it was confirmed that when the thermal spraying material containing these mixed crystals was sprayed, _{the proportion of Y 5} O ₄ F ₇ contained in the thermal spray coating increased as the solid solution ratio of _{YF 3 increased.} Was done. It was also confirmed that the porosity of the sprayed coating was reduced by increasing the solid solution ratio of _{YF 3.} FIG. 6 is a cross-sectional image of the thermal spray coating of Example 8. As is clear from comparison with the thermal spray coating of Example 5 shown in FIG. 5 (porosity 8%), it was confirmed that an extremely dense thermal spray coating was formed.

Further, in Example 8, the _{ratio of the Y 5} O ₄ F ₇ phase contained in the thermal spray coating is higher than the composition ratio _{of the Y 5} O ₄ F _{7 phase in the thermal spraying material.} Further, it can be seen that _{Y 2} O ₃ is not formed in the thermal spray coating by using the thermal spraying materials of Examples 7 and 8 in which the solid solution ratio of _{YF 3} is higher than that of Example 6. From these, a mixed crystal that is included in the spraying material has Y ₅ O ₄ F ₇ and confirmed to be decomposed into YOF by spraying environment. That is, when the mixed crystal is decomposed, the composition of the mixed crystal is gradually changed, and when the oxidation further progresses, it is precipitated as _{Y 5} O ₄ F _{7 constituting the mixed crystal, and Y 5} O ₄ F _It is considered that 7 is decomposed after passing through YOF having a lower proportion of fluorine when it is oxidized. The sprayed coatings of Examples 6, 7 and 8 had the same plasma erosion resistance, no alteration layer was observed, and the dust generation resistance was good as A to B. It is considered that the reason why the dusting property of the sprayed coating of Example 8 became B is that the composition of Y, O, and F _{approached that of YF 3.}

The thermal spraying materials of Examples 6 * to 8 * have the form of granulated particles. However, from the XRD analysis results, it was confirmed that each of them contained mixed crystals having the same composition as in Examples 6 to 8. _{As a result, Y 2} O ₃ is not formed in the thermal spray coating obtained by spraying the thermal spraying materials of Examples 6 * to 8 *, and because it contains mixed crystals, it is still sprayed even in the form of granules. It was confirmed that the decomposition of the thermal spraying material into oxides was suppressed. However, since the thermal spraying material is in the form of granules, the presence of unmelted particles was confirmed in the thermal spray coating, and as a result, the thermal spray coating had a slightly higher porosity and was more resistant than the thermal spray coatings of Examples 6 to 8. It was found that the plasma erosion characteristics and dust generation were inferior. However, both plasma erosion resistance and dust generation resistance are superior to those of the thermal spray coatings of Reference Examples and Examples 1 to 4, and the thermal spraying material contains mixed crystals, which suppresses material deterioration during thermal spraying and is of good quality. It was confirmed that a thermal spray coating could be formed.

[Embodiment 2]
Using the thermal spraying materials of Examples 5, 6 and 7 prepared in the first embodiment, the characteristics of the thermal spray coating obtained by thermal spraying under different thermal spraying conditions were investigated.
That is, in Example 5A, the thermal spraying material of Example 5 was used, and a commercially available plasma spraying device “SG-100” (manufactured by Praxair Surface Technologies) was used to generate argon gas 100 psi (0.69 MPa) and helium gas 110 psi (0. A thermal spray coating was formed by using a mixed gas of 76 MPa) as a thermal spraying gas and performing high-speed thermal spraying under the conditions of a voltage of 41.6 V and a current of 900 A.

Further, in Example 5B, the thermal spraying material of Example 5 was used, and a mixed gas of argon gas 50NLPM and hydrogen gas 10NLPM was used as the thermal spraying gas in a commercially available plasma spraying device “F4” (manufactured by Sulzer Mteco), and the voltage was increased. A thermal spray coating was formed by thermal spraying under the conditions of 70 V and a current of 600 A.
In Example 5C, the thermal spray coating was formed by setting the plasma generation conditions of the thermal spraying apparatus to a voltage of 70 V and a current of 600 A in the same manner as in Example 5B.

In Example 6A, a thermal spray coating was formed by using the thermal spraying material of Example 6 and performing high-speed thermal spraying under the same thermal spraying conditions as in Example 5A.
In Example 6B, a thermal spray coating was formed by using the thermal spraying material of Example 6 and spraying under the same thermal spraying conditions as in Example 5B.
In Example 7A, a thermal spray coating was formed by using the thermal spraying material of Example 7 and spraying under the same thermal spraying conditions as in Example 5B.

The characteristics of the sprayed coating thus obtained were investigated, and the results are shown in Table 3. The contents of each column in Table 3 are the same as those in Table 2.

(evaluation)
First, Example 5 and from 5B comparison, the spray gun in the F4 thermal spray gas by changing the nitrogen-containing gas, Y ₅ O ₄ spraying material consisting of melted powder F ₇ composition greatly changes during spraying , and a large amount of YOF phase, and a Y ₂ O ₃ phase has been found to be detected in the thermal spray coating. However, as shown in Examples 5A and 5C, it was confirmed that the change in the composition of the thermal spray coating tended to be suppressed by increasing the output of each thermal spraying device. The composition of the sprayed coating of Example 5B _{changed significantly from that of Y 5} O ₄ F ₇ , and the Y ₂ O ₃ phase was detected by XRD analysis. However, from the results of XRD analysis and XPS analysis, the thermal spraying materials of Examples 5A to 5C formed mixed crystals in the thermal spray coating by thermal spraying, and when exposed to plasma, a alteration layer was formed on the thermal spray coating. It was confirmed that it was not formed. However, there was no significant difference between Example 5 and Examples 5A to 5C in terms of plasma erosion resistance and the state of formation of the altered layer.

On the other hand, as shown in the example 6～6B, in the case of using a thermal spray material consisting of melted powder mixed crystal of Y ₅ O ₄ F ₇ and YF _3, maintaining a high fluorine content in the thermal spray coating It turned out that it could be sprayed. It was also found that the sprayed coating also contained mixed crystals. For example, in Example 6B, the spraying gas changes the composition of the thermal spraying materials by changing the nitrogen-containing gas spray gun in the F4, a large amount of Y ₂ O ₃ phase is detected during the thermal spray coating. However, the results of XRD and XPS, the _Y 2 _{O 3} phase forms a mixed crystal together with other detection phase such as _Y 5 _O 4 _{F 7,} the sprayed coating even when exposed to plasma It was confirmed that the altered layer was not formed. Further, the thermal spray coatings of Examples 6 to 6B have extremely high plasma erosion resistance and dust generation resistance even in the normal thermal spraying method (Example 6), as in the case of changing the thermal spraying conditions (Examples 6A and 6B). It turned out to be good. That is, it was found that the thermal spraying material _{contained a mixed crystal of Y 5} O ₄ F ₇ to achieve both plasma erosion resistance and dust generation resistance at a high level.
As described above, since the thermal spraying material of Example 6 contains mixed crystals, oxidative decomposition is suitably suppressed, and even if thermal spraying is not performed under special thermal spraying conditions, a sufficiently high-quality thermal spray coating can be obtained by a general thermal spraying method. Was found to be obtained. However, as shown in Examples 6A to 6B, when the thermal spraying material contains mixed crystals, the deterioration of the thermal spray coating is suppressed by further changing the thermal spraying conditions, and a thermal spray coating having extremely excellent dust generation resistance can be obtained. It was confirmed that it could be done.

The same can be confirmed from the comparison between Example 7 and Example 7A. That is, Example 7A, by changing the spray gun in the F4 thermal spraying gas to the nitrogen-containing gas, a large amount of Y ₂ O ₃ phase is detected during the thermal spray coating. However, this Y ₂ O ₃ phase _{forms a mixed crystal with the Y 5} O ₄ F ₇ phase and the like, and it is possible to realize a structure in which an altered layer is unlikely to be formed on the sprayed coating even when exposed to plasma. It was confirmed that.

[Embodiment 3]
In the third embodiment, as the thermal spraying material, the thermal spraying material of Example 8 (Examples 8a, 8b, 8A, 8B) prepared in the first embodiment and the granulation granulated in the production of the thermal spraying material of Example 8 are performed. Using a thermal spraying material (eg 8C, 8D) made of molten powder obtained by reducing the particle size of the particles, the thermal spraying conditions were variously changed to form a thermal spray coating. In Examples 8a and 8b, as in the second embodiment, a commercially available plasma spraying device "F4" (manufactured by Sulzer Mteco) was used as a thermal spraying device, and thermal spraying was performed by changing the output. Further, in Examples 8A to 8D, a cylindrical shroud device with a metal taber was extended and used at the tip of the barrel of the thermal spraying device “F4”. This shroud device has a double-tube structure and is water-coolable, and is provided with ports for blowing inert gas at two locations, the upstream side of the cylinder and the outlet. For thermal spraying, a thermal spray coating was formed by spraying using a mixed gas of argon gas / hydrogen gas / nitrogen gas as the thermal spraying gas. In Examples 8A and 8C, argon (Ar) gas was used as the shroud gas. In Examples 8B and 8D, nitrogen (N ₂ ) gas was used as the shroud gas.

The characteristics of the sprayed coating thus obtained were investigated, and the results are shown in Table 4. The contents of each column in Table 4 are the same as those in Table 2.

Since the thermal spraying material of Example 8 contained mixed crystals, it was confirmed that the thermal spray coatings of all the examples were composed of mixed crystals regardless of the thermal spraying device and the thermal spraying conditions. Further, even in the usual thermal spraying method (Example 8), the fluorine contained in the thermal spray coating is similar to the case where the thermal spraying device is changed (Examples 8a and 8b) and the shroud device is used in combination (Examples 8A to 8D). Since the amount was maintained high and the spraying was possible, it was found that a dense sprayed coating with a porosity of 3% could be obtained.
From the comparison of Examples 8, 8a and 8b, by changing the thermal spraying device from SG-100 to F4, a large amount of oxygen is introduced into the composition of the thermal spray coating, and the ratio of _{Y 5} O ₄ F _{7 increases.} all right. Further, when the thermal spraying device F4 was used under high output conditions, a relatively oxygen-rich YOF phase was detected from the XRD results, and it was confirmed that the introduction ratio of oxygen into the thermal spray coating was high. However, since the sprayed coating formed mixed crystals, it was found that the dust generation resistance when the sprayed coating was exposed to plasma was improved. Further, as shown in Examples 8A to 8D, it was confirmed that the oxidation of the sprayed coating was suppressed even when F4 was used by performing shroud spraying using a shroud device. Examples 8C and 8D are materials for thermal spraying having a fine particle size, and oxidation by thermal spraying is usually promoted. However, in Examples 8C and 8D, it was found that by adopting shroud thermal spraying, a thermal sprayed film having good plasma erosion resistance and the like can be formed although the dust generation resistance is slightly inferior. Regardless of the particle size of the thermal spraying material, using Ar gas as the shroud gas is less likely to form an altered layer when the thermal spray coating is exposed to plasma, resulting in dust generation resistance. It can be seen that an excellent thermal spray coating can be formed.

From the above, it was confirmed that the thermal spraying material disclosed herein does not contain rare earth element oxides and is difficult to be oxidized in thermal spraying practice. It was found that the effect of suppressing oxidation is not limited to the thermal spraying method, but is also suppressed by general thermal spraying. As a result, the content of rare earth element oxides in the sprayed coating can be suppressed, and a sprayed coating containing rare earth element oxyfluoride as a main component can be formed. This provides a thermal spray coating and a member with a thermal spray coating that has both plasma erosion resistance and dust generation resistance.
Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above.

Claims (5)

With the base material
A thermal spray coating provided on at least a part of the surface of the base material,
With
The sprayed coating is
Containing elements include rare earth elements, oxygen and halogen elements
Includes mixed crystals of rare earth element oxyhalides and rare earth element halides,
Base material with thermal spray coating. Yttrium is contained as the rare earth element, and
Fluorine is contained as the halogen element,
The base material with a thermal spray coating according to claim 1, wherein the mixed crystal contains a mixed crystal of yttrium oxyfluoride and yttrium fluoride. The base material with a thermal spray coating according to claim 1 or 2 , wherein the thermal spray coating is mainly composed of the rare earth element oxyhalide. The thermal spray coating, the oxide that does not contain rare earth elements, the thermal spray coating with the base material according to any one of claims 1-3. The following evaluation test:
a) The surface of the thermal spray coating of the base material with the thermal spray coating for evaluation is mirror-polished so that the mirror-polished surface is exposed to the member corresponding to the upper electrode in the chamber of the parallel plate type semiconductor device manufacturing apparatus. A member with a thermal spray coating for evaluation is installed;
b) A dummy run in which a silicon wafer having a diameter of 300 mm is placed on a stage in the chamber and plasma dry etching is performed under the following plasma generation conditions is performed on 2000 silicon wafers for 100 hours .
Chamber pressure: 13.3 Pa
Etching gas composition: Mixed gas of argon, carbon tetrafluoride, and oxygen Etching gas Flow rate: 1 L / min Plasma generation voltage: 13.56 MHz, 1500 W;
c) Next, a silicon wafer having a diameter of 300 mm for particle counting was placed on the stage in the chamber, and when halogen-based plasma was generated for 1 hour under the plasma generation conditions, it was deposited on the silicon wafer for particle counting. The number of particles having a diameter of 19 nm or more generated from the thermal spray coating is measured;
The base material with a thermal spray coating according to any one of claims 1 to 4 , wherein the number of particles generated by the above is 15 particles / cm ^{2 or less.}

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